Paul Ayscough is Director of Advanced Marketing at AMD and an evangelist for graphics and gaming.

Welcome to my first blog, I am not engineer, but I have been in the graphics and CPU space for over 15 years. I have seen the industry advance and grow from my early days in the game consol area, to working closely with API’s and game developers , to running marketing and communications at the old ATI and recently spending 3 years in one of the “BRIC” countries setting up and running sales and marketing for the old ATI.  Now, I work in advanced marketing, with the time to listen, think and talk about fun areas of our industry. My views tend to be simple – but hopefully clear, balanced and always open to debate!

There have been many words spoken and written about which is more important – the CPU or the GPU (graphics card) over the last 3 or 4 months.  Most words in this argument tend to take an extreme view, often the case when two sides have vested interests or just when two people argue.

Also, it is an old debate; one fueled by the ever increasing performance of CPU’s and GPU’s.  On the GPU side, we were all in wonder of the original film “Toy Story” when it first came out, today we can do more complicated graphics than Toy Story and in real time, and so the debate has moved on. Suffice to say, in my view, we have at least 10 years – maybe much longer – before we end up with ultra high resolution, totally immersive 3D renderings of the real world which are as good as those we can see with our very human eyes.  Who knows, by then, we may be working with “real 3D displays” of one type or another. On the CPU side, I once wondered why we would need more than a 386 class of processor; today with high frequencies and quad cores, we still have huge needs for more CPU processing power for AI and Physics in games, HD video, coding, decoding and transcoding in this multitasked Windows Vista-enabled world. 

For this bog, I will not be talking about advanced load balanced computing models based on CPU and GPU working together, (I will discus the area of Physics on GPU and or CPU in a future blog).

When I look at the competing views from two very significant companies, I always see ‘one side’ of the debate’ – actually both sides, but both sides tend to be very one sided!  In my opinion, games will likely always need more graphics performance (today on the GPU), some other applications will need more CPU performance; but even extreme gamers will always use their pc’s for more than just games and the workhorse, road-warrior laptop is often used to play games or watch a great movie.

So, I tried to think of reasons when balance is not the right answer in life, why one extreme would be right and the other wrong. Would you pay $2000 for an old car and then spend $5000 on the most cool audio system? (OK, yes I have that friend too).  Would you buy a $5,000 dress and mate it with last year’s $50 shoes. Well I don’t buy dresses, but you get the point!

So, in the PC space, would you mate a $40 entry level CPU with a $200 GPU? – no, the graphics card would be spending all it’s time waiting for data from the CPU – especially in games. Would you mate a high speed multi core CPU with an entry level graphics card – again, the GPU would likely not have the pixel pushing power to get the frame rates and quality you expect from the shiny new machine. Do you use your PC for just games or never for games – probably something in between…

And I am not just talking desktop PC’s – but mobiles or laptops too.  How many mid priced laptops have a great dual core CPU, but have extremely limited integrated graphics. This one drives me insane!  Spend $1000 on a laptop and you get a decent CPU but you usually only receive a low end integrated graphics chip! (This is starting to change – Integrated is getting better, look up reviews of the new AMD 780G integrated graphics chipsets in the AMD Puma platform and see that the graphics are actually good enough for many 3D intensive games and Blu Ray video playback).

So, I tried my simple theory with a few combinations of AMD CPU’s and AMD ATI Radeon GPU’s.

Caveat: I am no technical genius, all tests done with a friend, I had to change the motherboard for the Phenom CPU’s; however all other things were equal, 2 GB DDR2 etc and I used the CPU’s and GPU’s I could find around the office. See more technical details of the tests below…

CPU’s used and prices:
Low end: AMD ATHLON LE1600 $35.00
Mid range: AMD Athlon 64 X2 5200+ $80.00
High end: AMD Phenom 8750 $190.00

GPU’s used and prices:
Low end: AMD ATI Radeon HD 3450 256mb $34.00
Mid range: AMD ATI Radeon HD 3850 256mb $85.00
High end AMD ATI Radeon HD 4850 512mb $180.00

Prices:
As can be seen, we 3 well matched CPU and GPU price combinations, one low end pair, one mid range pair and one higher end pair with CPU/GPU pricing equivalence.

We tested with 3 applications:
Test one: 3DMark ’06
Test two: Crysis
Test three: 4 min VOB file to MPEG4 transcode.

Results (click on a graph below for a larger image):

So, what do we see?

In the graphically intensive test, 3D Mark ’06, we see that GPU is hugely more important than the CPU, in Crysis, the GPU is more important, but better CPU helps. In the transcode test, the CPU is the only important element. All scale as you would expect, higher end parts, better scores.

More importantly, we see that if you have a high end CPU and a low end GPU, your CPU is completely wasted in both the 3D Mark ’06 and Crysis tests.

And if you have a low end CPU and high end GPU, your 3DMark tests and Crysis score show that the GPU is waiting for the CPU

With the transcoding test (CPU intensive), the GPU is close to irrelevant.

Finally, if you use a balanced system, with CPU and GPU price equivalence, you have scores in all 3 tests that are in the middle; no weak link.

So, with an unbalanced system, either the CPU or the GPU is underutilized in any 3D intensive task. And for a system that can do 3D tasks and non 3D based tasks, again, having a balance seems the best way to use the $’s spent. It’s only if you never expect to do any 3D at all that a CPU centric system makes sense.

So, someone will always find an edge case where the rule can be broken. But for 90% of people who do a variety of different things on their PC, not just email and Skype, balance would seem to be the right way.

One thing I am happy with is that the debate is good and very overdue. I personally think we were too CPU centric for too long and the time has come to balance the system, especially in this new era of media centric computing!

Test specifics:

1. 3D Mark 2006 at 1680 X 1050 resolution. ATI Radeon 4850 and 3850 were done using 8X AA. ATI Radeon 3450 at 4X AA, due to limits on the board
2. Crysis game was run at 1680 X1050 resolution, level “contact” was used for test. “Fraps” was used to check frame rates. An average frame rate was used.
3. VOB file was 4 mins in duration. Original resolution was 780 X 480. Decode resolution for the MGEP4 was 480 X 208

Pricing: Prices were taken from Newegg, Week of July 28^th 2008. Lowest prices were taken when more than one was available

Paul Ayscough is Director of Advanced Marketing at AMD and an evangelist for graphics and gaming.  His postings are his own opinions and may not represent AMD’s positions, strategies or opinions. Links to third party sites are provided for convenience and unless explicitly stated, AMD is not responsible for the contents of such linked sites and no endorsement is implied.