High Performance PC Rig Questions

[Chizume]

Hello,

I'm in the process of getting myself a new computer and I am currently studying the options. Below is a custom build I have put together reading from different forums around the web.

I'm starting a Game Development - Design program in a few weeks which will keep me busy for 3 years and after that I want to potentially work in the industry.

So what I want is to be able to play games on very high/high graphics for the next 3-5 years. Additionally I wish to be able to handle 3D softwares such as Maya, Zbrush, etc and game engines such as Unity and Unreal Engine 3 (and 4), etc.

Note that this would be my first custom build. Also I have never tried overclocking before. My last computer was a complete build which I bought 4 years ago. However, I have read a lot online lately and think I have a general understanding of what is required.

Would the build perform as intended? Is it weak, overkill, would it work at all?

The Build

CPU	Intel Core i5 3570K 3.4 GHz I wish to overclock this a bit, to unlock more of its potential.
GPU	Nvidia GeForce GTX 670 OC 980 MHz, (1058Mhz Boost Clock) 2048 MB, GDDR5 Overclocked already, but is said to be able to be overclocked further.
HDD	1 TB (7200rpm), SATA 6,0 Gbit/s
RAM	8 GB, 2x4096MB, DDR3 1600MHz
Motherboard	MSI Z77A-GD55 ATX
Power Supply	FSP Aurum 650W 80+ Gold Modular
+Cooling	Cooler Master Hyper 212 EVO

> Link to build with more details on all its components.
The link is in Swedish but most technicalities are global anyway; Let me know if there is anything you cannot find a translation for and I'll be happy to translate.

 

[Ironside]

Looks pretty decent, the only thing (in case you'd like some increase in speed) is to replace CPU with a 2011 type to support 4 channeled RAM and then get either 8GB (4x2GB) or 16GB (4x4GB). The increase in speed of RAM is about 10%.

 

[Chizume]

Looks pretty decent, the only thing (in case you'd like some increase in speed) is to replace CPU with a 2011 type to support 4 channeled RAM and then get either 8GB (4x2GB) or 16GB (4x4GB). The increase in speed of RAM is about 10%.

You mean an i7?

10% speed increase = 10% price increase but possibly affordable.

What makes 8 MB (4x2GB) faster than 8MB (2x4GB)? Not that 16MB (4x4GB) is that much more expensive.

Also if I were to overclock the CPU (the i5 3570K or i7 3770K) to ~4,5GHz do you think the cooling would be sufficient?

 

[The Reborn Devil]

Make sure you get a case that can fit all that stuff in it. Space for additional fans/radiators is also recommended.

Anyway, if gaming is your primary concern, and particularly demanding 3D, I'd recommend an AMD CPU instead of Intel. Particularly the AMD FX-8150 (8-core CPU). If you can get your hands on it, the FX-8170 would be preferable. While having the quite obvious increased processor count and clock speed, as well as lower pricing than Intel CPU's, it also excels at gaming. Tests have shown that it's able to get more "juice" out of your GPU when playing demanding games (compared to equivalent Intel CPUs). The only thing the AMD FX-8150 CPU lost at in the comparison was Photoshop performance as well as decoding of videos.

Edit:

Btw, if you're really crazy about gaming, why don't you go for the XFX Radeon HD 7970 1000MHz 3GB GPU? As of right now, the Radeon HD 7970 costs the same as your GTX 670 (over here anyway) and it's considered the most powerful consumer GPU yet¹.

Full specifications for the Radeon HD 7970:

:D

• 1GHz Engine Clock (up to 1.05GHz with boost)
• 3GB GDDR5 Memory
• 1500MHz Memory Clock (6.0 Gbps GDDR5)
• 288GB/s memory bandwidth
• 4.3 TFLOPS Single Precision compute power
• 1.01 TFLOPS Double Precision compute power
• GCN Architecture
  • 32 Compute Units (2048 Stream Processors)
  • 128 Texture Units
  • 128 Z/Stencil ROP Units
  • 32 Color ROP Units
  • Dual geometry units
• Dual Asynchronous Compute Engines (ACE)
• PCI Express 3.0 x16 bus interface
• DirectX® 11.1-capable graphics
  • 9th generation programmable hardware tessellation units
  • Shader Model 5.0
  • DirectCompute 11
  • Accelerated multi-threading
  • HDR texture compression
  • Order-independent transparency
• OpenGL 4.2 support
  • Partially Resident Textures (PRT)
    • Ultra-high resolution texture streaming technology
• Image quality enhancement technology
  • Up to 24x multi-sample and super-sample anti-aliasing modes
  • Adaptive anti-aliasing
  • Morphological Anti-Aliasing (MLAA) 2.0
  • DirectX® 9/10/11 Super Sample Anti-Aliasing (SSAA)
    • Automatic LOD adjustment (Requires AMD Catalyst™ 12.4 or higher)
  • 16x angle independent anisotropic texture filtering
  • 128-bit floating point HDR rendering
• AMD Eyefinity multi-display technology
  • Up to 6 displays supported with DisplayPort 1.2 Multi-Stream Transport
  • Independent resolutions, refresh rates, color controls, and video overlays
  • Display grouping
    • Combine multiple displays to behave like a single large display
• AMD App Acceleration
  • OpenCL 1.2 Support
  • Microsoft C++ AMP
  • DirectCompute 11
  • Double Precision Floating Point
  • AMD HD Media Accelerator
    • Unified Video Decoder (UVD)
      • H.264
      • VC-1
      • MPEG-2 (SD & HD)
      • MVC (Blu-ray 3D)
      • MPEG-4 Part 2 (DivX/Xvid)
      • Adobe Flash
      • DXVA 1.0 & 2.0 support
    • Video Codec Engine (VCE)
      • Multi-stream hardware H.264 encoder
      • Full-fixed mode: 1080p @ 60 FPS encoding
      • Hybrid mode: Stream Processor-assisted encoding
    • Enhanced Video Quality features
      • Advanced post-processing and scaling
        • Deblocking
        • Denoising
        • Automatic deinterlacing
        • Mosquito noise reduction
        • Edge enhancement
        • 3:2 pulldown detection
      • Advanced video color correction
        • Brighter whites processing (Blue Stretch)
        • Independent video gamma control
        • Flesh tone correction
        • Color vibrance control
        • Dynamic contrast
        • Dynamic video range control
• AMD HD3D technology
  • Stereoscopic 3D display/glasses support
  • Blu-ray 3D support
  • Stereoscopic 3D gaming
  • 3rd party Stereoscopic 3D middleware software support
• AMD CrossFire™ multi-GPU technology
  • Dual, triple or quad-GPU scaling
• Cutting-edge integrated display support
  • DisplayPort 1.2 HBR2
    • Max resolution: 4096x2160 per display
    • Multi-Stream Transport
    • 21.6 Gbps bandwidth
    • High bit-rate audio
    • Quad HD/4k video support
  • HDMI® (With 4K, 3D, x.v.Color™ and Deep Color)
    • Max resolution: 4096x2160
    • 1080p60 Stereoscopic 3D
    • Quad HD/4k video support
  • Dual-link DVI with HDCP
    • Max resolution: 2560x1600
  • VGA
    • Max resolution: 2048x1536
• Integrated HD audio controller
  • Output protected high bit rate 7.1 channel surround sound over HDMI with no additional cables required
  • Supports AC-3, AAC, Dolby TrueHD and DTS Master Audio formats
• AMD PowerPlay™ power management technology
  • Automatic power management with low power idle states
• AMD PowerTune technology
  • Intelligent TDP management technology
  • Dynamic clockspeed/performance enhancement for games
• AMD ZeroCore Power technology
  • Ultra-low idle power when the system’s display is off
  • Efficient low power mode for desktop work
  • Secondary GPUs in an AMD CrossFire™ technology configuration power down when unneeded
• AMD Catalyst™ graphics and HD video configuration software
  • Software support for Windows® 7, Windows Vista® and Windows® XP.
  • AMD Catalyst™ Control Center - AMD Catalyst™ software application and user interface for setup, configuration, and accessing features of AMD Radeon products.
  • Unified Graphics display driver - AMD Catalyst™ software enabling other PC programs and devices to use advanced graphics, video, and features of AMD Radeon™ products.

1. In tests by AMD as of May 22, 2012 on single-GPU graphics cards, the AMD Radeon™ HD 7970 GHz Edition showed higher average performance than the NVIDIA GeForce GTX 680 in the following games/apps: Formula 1 2010, Civilization V, StarCraft II, Just Cause 2, Unigine Heaven, Left 4 Dead 2, Enemy Territory: Quake Wars, The Elder Scrolls V: Skyrim, DiRT 3, The Chronicles of Riddick: Assault on Dark Athena, Crysis Warhead, Metro 2033 (4xAA), and Hard Reset (MLAA). All applications were evaluated at 2560x1600 with 8xAA and 16xAF unless otherwise noted.

 

[Ironside]

You mean an i7?

10% speed increase = 10% price increase but possibly affordable.

What makes 8 MB (4x2GB) faster than 8MB (2x4GB)? Not that 16MB (4x4GB) is that much more expensive.

Also if I were to overclock the CPU (the i5 3570K or i7 3770K) to ~4,5GHz do you think the cooling would be sufficient?

Difference between 2x4GB and 4x2GB is the channels, 2x4GB is dual channel while 4x2GB is quad channel.

 

[Chizume]

Make sure you get a case that can fit all that stuff in it. Space for additional fans/radiators is also recommended.

Anyway, if gaming is your primary concern, and particularly demanding 3D, I'd recommend an AMD CPU instead of Intel. Particularly the AMD FX-8150 (8-core CPU). If you can get your hands on it, the FX-8170 would be preferable. While having the quite obvious increased processor count and clock speed, as well as lower pricing than Intel CPU's, it also excels at gaming. Tests have shown that it's able to get more "juice" out of your GPU when playing demanding games (compared to equivalent Intel CPUs). The only thing the AMD FX-8150 CPU lost at in the comparison was Photoshop performance as well as decoding of videos.

I was thinking of this http://www.fractal-design.com/?view=product&category=2&prod=66 case.

Intel and Nvidia feels like "safe" options, but it is possibly a false sense of security. I also know there's a lot of old loyalty to these.

I googled some on the CPU and GPU you mentioned. Radeon HD 7970 definitely seems to outperform everything. But the FX-8150 seems surrounded by bad reviews and tests.

Something I can't really get a grip on however with the Radeon HD 7970; Would a quad-core CPU hold down its true potential?

EDIT: What CPU did AMD use with this test?

 

[BlargHonk]

I was thinking of this http://www.fractal-design.com/?view=product&category=2&prod=66 case.

Fractal is a new company, but everything from them sofar has been top-notch. Lian-Li quality without the price hike.

I googled some on the CPU and GPU you mentioned. Radeon HD 7970 definitely seems to outperform everything. But the FX-8150 seems surrounded by bad reviews and tests.

Something I can't really get a grip on however with the Radeon HD 7970; Would a quad-core CPU hold down its true potential?

EDIT: What CPU did AMD use with this test?

In reviews it's common practice to use the most powerful CPU available inorder to test the GPU's without bottlenecks. That said, an Intel Quad is FINE for even a GTX690/HD6990 when being used for gaming.

The HD7970 is above the GTX670 in terms of performance, about halfway between it and the GTX680, while the "GHZ Edition" is about equal with the GTX680.

In terms of pricing, HD7970's are about $20 more than GTX670's, while the GHZ Edition is $50 LESS than the GTX680

You could of course get this: http://www.newegg.com/Product/Product.aspx?Item=N82E16814103210 Which is essentially a "GHZ Edition" that was made before the official release, might not overclock as well, who knows.

 

[Dr Super Good]

It is "top range" yet uses an I5... I7 is Intel's "performance" series.

Nothing you buy now will be able to run games on very high in 5 years if computer trends hold true.

 

[Ralle]

I would not expect a high end GPU of today to be able to run at highest graphics in 5 years. I would actually prefer to buy one of the more popular ones that are not as ridiculously priced. You can then buy a new GPU in 3 years and have more awesome along the way.

 

[Chizume]

It is "top range" yet uses an I5... I7 is Intel's "performance" series.

That's why I came here for advice.

Anyway, I'm not going to lie. I do obviously have a limited budget. As Ralle suggest it would perhaps be better to aim not for the ultimate gaming computer, but one that will work well for a couple of years and then get a new one. Unfortunately prices are exponential, but that is what to be expected.

Good Enough Edition

CPU	Intel Core i5 3570K 3.4 GHz I wish to overclock this a bit, to unlock more of its potential.
GPU	Nvidia GeForce GTX 670 OC 980 MHz, (1058Mhz Boost Clock) 2048 MB Overclocked already, but is said to be able to be overclocked further.	OR	Gigabyte Radeon HD7950 3072MB 900 MHz Appears to be about the same efficiency judging from various benchmark tests, but slightly cheaper. Its the exact same size the case's maximum allows, will this make it troublesome to assemble?
RAM	8 GB, 2x4096MB, DDR3 1600MHz I think the idea of going 4x will not increase performance as much as price. Would there however be any significant difference between 2x4 and 2x8?
Motherboard	MSI Z77A-G43 ATX Slightly cheaper version, without SLI which I don't need unless I intend to use 2 GPUs I take it.
Power Supply	FSP Aurum 550W 80+ Gold Modular Reduced to a 550W. Recommendation for both GPUs is 500W so it should be enough, right?
HDD	1TB Seagate Barracuda 3,5'' (7200rpm) SATA 6Gbit/s Okay so here's the one.

So I've stripped it as much as I could without reducing its power. What do you guys think? (see descriptions/questions in small text below each component)

 

[Ironside]

Replace the HD with the HHD you had previously, this one is half the speed.
What you have now is a HD, before it was a HHD. HHD is a little more expensive than a HD but the speed can compare with a SSD.

 

[mckill2009]

in 3-5 yrs time, that choice of yours maybe weak, coz computer hardware grows faster nowadays, your 1TB HDD maybe 3TB on that day ...

 

[Chizume]

Alright, took back the HDD, thanks.

Any opinions on the GPU and Memory?

 

[Ironside]

GPU is fine, as for the Ram, like I said, only thing you can do is switch to quad channel, else that's that, you're good to go.

 

[Edhel-dur]

in 3-5 yrs time, that choice of yours maybe weak, coz computer hardware grows faster nowadays, your 1TB HDD maybe 3TB on that day ...

The point is that you get a really good motherboard. The point is, as time passes, just in case, you can add another HDD, more RAM, etc. Your motherboard looks good. Intel + Nvidia, good pick there. Max 32gb RAM, looks good.

Make sure to get a good Power Source so tension fluctuations won't burn your PC.

Also you need good ventilation. I know you are from Sweden yet still, you need a good case which provides good ventilation to keep those temperatures down. Ofc you need good coolers. For both I recommend THERMALTAKE.

You must make sure that your CPU never ever reaches 100 degrees Celcius, Video card and HDD never reach 80 degrees. I live in Romania and this summer was the hottest ever, and with 1 really big and good CPU cooler + 1 large fan to the side and 1 small fan in the back, temperatures would never go more than 60 degrees celcius, which is good. A really high temperature on your components will degrade them faster and slow your PC down.

--------------------

Personally, even with the technological advancement, your config should be fairly good and hold it's own for about 5-6 years. I doubt that in 6 years we will need more than 32gb RAM DDR3 and 2x Nvidia Geforce with 2048 RAM and an i5 CPU to run games on max settings.

 

[Chizume]

Personally, even with the technological advancement, your config should be fairly good and hold it's own for about 5-6 years. I doubt that in 6 years we will need more than 32gb RAM DDR3 and 2x Nvidia Geforce with 2048 RAM and an i5 CPU to run games on max settings.

Assuming I want to add more parts in a year or two for increased performance. For example bump the 2x4MB memory to 4x4MB. Would I have to replace the CPU to get anything out of additional Memory cards at all?

The current motherboard doesn't support SLI. But if I changed to one that supported it; would it be viable option to go with a GTX 670 OC and later add another GPU?

What is the difference in performance using a single powerful GPU compared to two less powerful ones?

The Fractal Design Define R3 case is quite spacious and comes with 2x 120mm (1350rpm) fans. The CPU and GPU obviously come with their own fans. I heard the i5 3570K cooler was alright. But still I may need to replace it with a better one if I am to overclock it (not certain here).

The PSU seems like a solid choice. I've taken a fancy to the brand FSP.

I like to explore my option thoroughly though.

 

[Dr Super Good]

I think the idea of going 4x will not increase performance as much as price. Would there however be any significant difference between 2x4 and 2x8?

More memory does not increase performance past larger file I/O caches. For the most part it will perform the same as a system with 4 GB total memory unless it constantly needs to page files in and out.

 

[Ironside]

To return back to the quad channel discussion, you should provide me with the price for the current ram and CPU you have on the list, then I can see if I can find you a 2011 set i7 without a high price increase.

The Ram itself, either 2x4GB or 4x2GB should be pretty much same price, the only difference will be the CPU, because it needs to be a 2011 set i7 one.

Also, if you're buying online, please provide me with the site where you'll order it from.

 

[Chizume]

Component	SEK	EUR
MSI Z77A-G43 ATX	900	110
Crucial 8GB (2x4096MB) CL8 1600MHz Ballistix Tactical	500	60
Intel Core i5 3570K 3,4Ghz (Ivy Bridge)	2000	240
MSI GeForce GTX 670 2048MB OC	3500	425
Fractal Design Define R3 USB 3.0, Titanium	700	85
FSP Aurum 550W 80+ Gold Modular	1000	120
Windows 7 Home Premium 64-bit English OEM	1000	120
Assembly and testing of computer with chosen components	800	95
Total	10400	1255

http://www.inet.se/

 

[Ironside]

Component	SEK	EUR
MSI Z77A-G43 ATX	900	110
Crucial 8GB (2x4096MB) CL8 1600MHz Ballistix Tactical	500	60
Intel Core i5 3570K 3,4Ghz (Ivy Bridge)	2000	240
MSI GeForce GTX 670 2048MB OC	3500	425
Fractal Design Define R3 USB 3.0, Titanium	700	85
FSP Aurum 550W 80+ Gold Modular	1000	120
Windows 7 Home Premium 64-bit English OEM	1000	120
Assembly and testing of computer with chosen components	800	95
Total	10400	1255

http://www.inet.se/

The Ram would cost about the same, the CPU is about 100€ more.
Now questions:

1. Why are you buying the OS when you can get it for free (PM me if you need help on how), if you simply want it for legal reasons, then alright.
2. Are you sure the 550W supply is enough?
3. Also provide link on inet to the motherboard so I can see all it offers

 

[Chizume]

The Ram would cost about the same, the CPU is about 100€ more.
Now questions:

1. Why are you buying the OS when you can get it for free (PM me if you need help on how), if you simply want it for legal reasons, then alright.
2. Are you sure the 550W supply is enough?
3. Also provide link on inet to the motherboard so I can see all it offers

1. Legal reasons, and because they will install it with the assembly-thingy. I may just save myself 200€ by building it myself and go without the OS.
2. I am not sure of anything. Not 100% sure on how to measure what the components need in total. I took the wattage recommendation for the GPU (500w) plus 50.
3. Motherboard Page

With a 2011 socket I also need to change the motherboard and they seem to be another 100€.

 

[Dr Super Good]

1. Why are you buying the OS when you can get it for free (PM me if you need help on how), if you simply want it for legal reasons, then alright.

Unless you were going to tell him to install a free Unix distribution like Unbuntu, how dare you say this.

 

[mckill2009]

Wow that's too expensive for a computer, I can get it in less than 600EUR without the OS...

 

[Chizume]

Wow that's too expensive for a computer, I can get it in less than 600EUR without the OS...

Not in Sweden it ain't. If I were to purchase all the parts separately for the cheapest prices in separate Swedish stores I'd save a total of about 15-25€.

Buying one abroad is ineffective as well; as importing it will put the price tag up to about the same as when buying it here.

 

[Edhel-dur]

The current motherboard doesn't support SLI. But if I changed to one that supported it; would it be viable option to go with a GTX 670 OC and later add another GPU?

Yeah but it has to be exactly the same.

What is the difference in performance using a single powerful GPU compared to two less powerful ones?

Having two less powerful GPU is like having multiple cores. They aren't necessarily better at doing one thing, but they are better at distributing the load when doing two things at the same time. I recommend having one powerful GPU and later on, if need be, add a second one.

The Fractal Design Define R3 case is quite spacious and comes with 2x 120mm (1350rpm) fans. The CPU and GPU obviously come with their own fans. I heard the i5 3570K cooler was alright. But still I may need to replace it with a better one if I am to overclock it (not certain here).

I noticed that it has a fan in the front. My case came like that too, but it's not necessarily a good thing. It works only if the room it finds itself is clean like in the hospital, no dust & no smoke! If the fan in the front is placed so it brings air from the outside into the case, if the case is placed in a dusty room, what will happen is that fan will bring all the dust in the case, and since you place the HDDs in the front, the dust will literary ruin your HDDs over time. If the room is sterile than having a fan in the front which brings cold air into the case is a good thing. Also you cannot place the case on the floor.
However personally I would just try and move that fan from the front of the case, to the side/back/top of the case and placed in such a way to get air out from the case. Here is a good article about Computer Cooling.

The PSU seems like a solid choice. I've taken a fancy to the brand FSP.

My knowledge of PSU isn't that good.



From my own experience, where my PC is 5-6 years old, and when I bought it, it was the best in line (well at least very close), but now I can't play games on max video settings unless I upgrade my Memory and Video Card.

Needless to say my motherboard doesn't support DDR3, or a second Video Card, it does support however up to 16GB DDR2, so if I wanted too I could just get 16GB DDR2 and better Video Card and I think I could play games at max settings.

Currently I have an Intel Core 2 Quad (equivalent to an i3), 2GB DDR2 and a GeForce 8600 GTS.

 

[The Reborn Devil]

Intel and Nvidia feels like "safe" options, but it is possibly a false sense of security. I also know there's a lot of old loyalty to these.

Yeah, I know a lot of people care about brands. I've had an nVidia GPU myself, but now I have an ATI GPU and AMD CPU and I'm very satisfied. Especially with the price. My nVidia GPU melted one day and I needed a replacement. I was initially sceptic about the ridiculously cheap HIS Radeon HD 5750 which I looked at, but I decided to get it. It delivered more than I could've hoped for. Played Skyrim on almost max detail @ 1920x1080. Now I have the XFX Radeon HD 7750 Black Edition.

Radeon HD 7970 definitely seems to outperform everything.

Indeed it does outperform everything.

But the FX-8150 seems surrounded by bad reviews and tests.

From my searching it seems to be surrounded by both bad and very good reviews and tests. I hear some say it's shit, others say it outperforms the latest Intel CPU's. Tests I've seen either put it below, close or above the Intel CPUs. It kinda depends on the test. Like I said with the gaming, if that is your primary concern, then the AMD CPU would perform better. However, as noted it falls short in other things such as Photoshop performance and video encoding.

Something I can't really get a grip on however with the Radeon HD 7970; Would a quad-core CPU hold down its true potential?

Depends on the CPU, but simply put I'd say yes. However, in a sense, the FX-8150 is quad-core, because each individual core is smaller than what you'd find in other quad-core CPUs. AMD CPUs are built for multi-threading performance and they're able to get the most out of the GPU.

EDIT: What CPU did AMD use with this test?

I assume you mean the GPU test? Well, ironically enough they used an Intel CPU, the Intel i7-3960X to be exact.
This is the full build:
CPU: Intel Core i7-3960X (3.33GHz)
MOBO: MSI X79A-GD65
RAM: 16GB DDR3-1600
OS: Windows 7 x64.

Drivers:
AMD Radeon HD 7970 GHz Edition evaluated with AMD Catalyst 8.973.
NVIDIA GeForce GTX 680 evaluated with NVIDIA ForceWare 301.10 WHQL.

Basically, that would mean with the FX-8150 (or 8170 hurr hurr), it would more than outperform the GTX 680.

The HD7970 is above the GTX670 in terms of performance, about halfway between it and the GTX680, while the "GHZ Edition" is about equal with the GTX680.

The GHz Edition outperforms the GTX 680 in gaming. Also, the regular HD 7970 isn't halway between the GTX 760 and the GTX 680. The GHz Edition only has a slightly higher engine and memory clock speed.

In terms of pricing, HD7970's are about $20 more than GTX670's, while the GHZ Edition is $50 LESS than the GTX680

Different countries have different prices it would seem. I found that the HD 7970 GHz Edition is $5 LESS than the GTX 670. I haven't compared the price with the 680. Didn't really seem necessary as I assume the 680 is more expensive than the 670.

Herp, long post is long, and I've only looked at 2 posts. Wooooo...

Edit: Just took a short peak at the build you currently have in mind. I would invest in a better PSU as that would allow you to buy a second GPU, instead of buying an entirely new GPU. It would be cheaper and it would give you more performance. No need to go above 1000W though. Afaik 800W should be enough for 2x HD 7970.

 

[BlargHonk]

Having two less powerful GPU is like having multiple cores. They aren't necessarily better at doing one thing, but they are better at distributing the load when doing two things at the same time. I recommend having one powerful GPU and later on, if need be, add a second one.

Sorry, not how it works. It simply slaves the other GPU into performing the same task as the main GPU, helping it along, it will distribute yes, but not to two applications. A good example of something Very similar is RAID 0 for HDD's

A few (older) games do not support Crossfire/SLI either, so be warned. The scaling isn't 100% either, closer to 90% for Crossfire and 85% for SLI. This is lessened further in Triple or Quad, to the point where three GTX680's are equal to two GTX690's, despite the GTX680's costing $500 less total.