The CPU vs GPU Debate

Some months ago, NVIDIA went on the official warpath against Intel, bringing the CPU versus GPU debate into full force. If you missed it, Jen-Hsun Huang basically said that CPUs are plenty powerful now, and that consumers should be spending their hard-earned money on video cards rather than big CPUs. Just about every review site took off with this idea, and began their own exaggerated testing that doesn't really answer anyone's questions. I'm going to try to wrap this all up for you now with a no-nonsense editorial about the whole situation.

The recent reviews I've read dealing with this situation seek to answer a pretty easy question: given $1000, should you buy a QX9770 or two 9800GX2s? However, this only gives us the two options and nothing in the middle; there is no option for a moderately priced CPU and a moderately priced GPU, only the extremes which are easy to quantify. To add to the consumer confusion, these sites are usually offering gaming tests alone to prove one side or another, where a pair of 9800GX2s can really shine. But let's look at the whole picture for a minute, shall we?

When my NVIDIA representative called me and asked about this, I told him that I would much rather have a fast dual-core and a quick video card than a slower quad-core and a slower video card. For instance, an E8400 with an 8800GT will be a better package for general purpose computing than a Q9450 with an 8500GT. However, it is very easy to tip that scale in either direction once actual usage comes into play. If I am a gamer, the 8800GT matters more, but if I'm a video editor, the Q9450 matters more. Therefore, we can say that in this price range, you really must tailor the PC to the needs of the customer, and neither product is "better" than the other.

Let’s take a peek at the upper end of this debate, which is where most everyone else is looking. One real-life situation here is that you have a set budget for a PC and that budget is $3,500. That means you have roughly $700 to spend upgrading your Thor. So should you get a QX9650 or two 9800GX2s?

Intel would have you believe that the QX9650 will be a better investment, but I am here to steer you away. In all reality, there are very few programs that can actually use four CPU’s. Need proof? Look at any CPU review in the past year. You’ll see things like Cinebench, Maya 3D, proprietary benchmarks, and DIVX encoding. Let’s face it, if you are doing serious 3D modeling or video editing, you’re better off putting $700 towards a dual-socket, 8-core workstation than a QX9650.

On the other hand, are two 9800GX2s really worth it? Well let’s look at the hardware. NVIDIA’s current king is the G92 processor, which is the heart of everything from the sub-$200 8800GT to the $550+ 9800GX2. With two of the GX2s, you get a total of 4 GPUs which is actually quite the magic number. We see excellent scaling from one to two GPUs and even decent scaling from two to three GPUs in current games. However, scaling from three to four GPUs is rather pathetic due to current programming limitations.

So we’ve ruled out Quad-SLI, because of modest gains from Triple-SLI, but in all reality, we can't even recommend Triple-SLI unless you just have to have it to get a better benchmark score. In the price-per-frame game, two 8800GT cards perform pretty close to two 9800GTX cards, and the third one only pumps up the score by around 10%, hardly anything to make what was once unplayable now playable. I'd have to say stick with two 8800GTs for now, and use the other $500 somewhere else.

We've given NVIDIA an extra $200 for a second card, but what about the other $500? I’ll let you in on a little secret: CPUs and GPUs do not make a computer by themselves. Hard drives, opticals, memory and sound cards all make up this machine, and putting a little more into any of these components can give you a much better return on your investment than a CPU or GPU upgrade. If it were my $500 for my general-purpose PC, I’d have to say 8GB of RAM, Blu-Ray Burner and 300GB Velociraptor would all be on my list before a Core 2 Extreme or Quad-SLI. Heck, I might even take a Sound Blaster X-Fi before plopping down over $1000 for processor that will still be outdated in less than one year.

Well there you go, the real winner in the CPU versus GPU debate is: everything else.