The RV870 Story: AMD Showing up to the Fight
by Anand Lal Shimpi on February 14, 2010 12:00 AM EST- Posted in
- GPUs
The Cost of Jumping to 40nm
This part of the story could almost stand on its own, but it directly impacts much of what happened with Cypress and the entire Evergreen stack that it’s worth talking about here.
By now you’ve most likely heard about issues with TSMC’s 40nm process. While the word is that the issues are finally over, poor yields and a slower than expected ramp lead to Cypress shortages last year and contributed to NVIDIA’s Fermi/GF100 delay. For the next couple of pages I want to talk about the move to 40nm and why it’s been so difficult.
The biggest issue with being a fabless semiconductor is that you have one more vendor to deal with when you’re trying to get out a new product. On top of dealing with memory companies, component manufacturers and folks who have IP you need, you also have to deal with a third party that’s going to actually make your chip. To make matters worse, every year or so, your foundry partner comes to you with a brand new process to use.
The pitch always goes the same way. This new process is usually a lot smaller, can run faster and uses less power. As with any company whose job it is to sell something, your foundry partner wants you to buy its latest and greatest as soon as possible. And as is usually the case in the PC industry, they want you to buy it before it's actually ready.
But have no fear. What normally happens is your foundry company will come to you with a list of design rules and hints. If you follow all of the guidelines, the foundry will guarantee that they can produce your chip and that it will work. In other words, do what we tell you to do, and your chip will yield.
Global Foundries' 2010 - 2011 Manufacturing Roadmap
The problem is that if you follow every last one of these design rules and hints your chip won’t be any faster than it was on the older manufacturing process. Your yield will be about the same but your cost will be higher since you’ll bloat your design taking into account these “hints”.
Generally between process nodes the size of the wafer doesn’t change. We were at 200mm wafers for a while and now modern fabs use 300mm wafers. The transistor size does shrink however, so in theory you could fit more die on a wafer with each process shrink.
The problem is with any new process, the cost per wafer goes up. It’s a new process, most likely more complex, and thus the wafer cost is higher. If the wafer costs are 50% higher, then you need to fit at least 50% more die on each wafer in order to break even with your costs on the old process. In reality you actually need to fit more than 50% die per wafer on the new process because yields usually suck at the start. But if you follow the foundry’s guidelines to guarantee yield, you won’t even be close to breaking even.
The end result is you get zero benefit from moving to the new process. That’s not an option for anyone looking to actually use Moore’s Law to their advantage. Definitely not for a GPU company.
The solution is to have some very smart people in your company that can take these design rules and hints the foundry provides, and figure out which ones can be ignored, and ways to work around the others. This is an area where ATI and NVIDIA differ greatly.
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papapapapapapapababy - Sunday, February 14, 2010 - link
Ok, ok, great read, but i have to hate a bit, 1,2,3 GO! hey Carrell here is my top priority feature for your next PRS1 -Drivers that dont suck ass-
"The performance was still a problem and the RV740 was mostly lost as a product" ...
the fuk? the 4770 is the BEST card i ever had, PERIOD. cheap, fast, cool, the perfect RV770, thanks !
bla bla Carrell "He’s single handedly responsible for getting Eyefinity included in the Evergreen stack"
Meh? who gives a sht. , Carrell give me console like gpu scaling, so we can finally play crysis at 1080p, another one for that PRS
"Carrell went to David Glenn, head of software engineering at ATI and asked"
drivers that dont suck, please?
" There were also game compatibility concerns that made ATI not interested in the software approach"
Lol i wonder why? i think i know why. Hardware, hardware, what about the software,Carrell?
ok, thats it. not much to complain this time, flawless job ati guys
f0d - Sunday, February 14, 2010 - link
long time reader/first time postingive never felt the need to post anything but with this article i really wanted to say:
"thank you"
the insights we get in these articles is amazing (i also read the first when it was done)
i like the "no technical or maketing bs" writing of this story and all the little pieces of information like with the eyefinity story and sideport
please do as much of these type of stories as possible - it must be difficult to talk to the right people and get the right information out of them and also be allowed to publish it but it makes a great read
Robert Kooijman - Sunday, February 14, 2010 - link
Awesome article Anand!Also specially created an account to inform you how impressed I am with articles like these. A real treat these behind the scenes stories in non-marketing language. Keep 'm coming, compliments!
- Friday, February 19, 2010 - link
bravowhen do the (tech industry) book's come out??
Kryten - Sunday, February 14, 2010 - link
Informative, interesting, inspirational, edifying and very well written. Here's hoping for more research and articles like this.greenguy - Sunday, February 14, 2010 - link
Hi Anand, I've been reading your stuff for 3 years or so, I just created an account to tell you how awesome that article was. Very nice work. This sort of content is why I read Anandtech. (My other favorite articles have been the SSD articles and the i5-750 article.)I especially like to hear about AMD/ATI - I like having a serious competitor to Intel out there, and I commend AMD for opening up their graphics card documentation. I hope that they continue to fund the Linux driver development (both open and closed source). I also hope their CPU division can put the heat on Intel again, especially on the low power front.
at80eighty - Sunday, February 14, 2010 - link
Anand I was just telling someone yesterday how I wish you guys got more popularity for the different approach you guys havebetween articles like this and the new beta Bench tab - I think I'm really looking forward to your proposed changes you promised this year
insurgent - Sunday, February 14, 2010 - link
I had a really great time reading the article, thanks!Markstar - Sunday, February 14, 2010 - link
Also a big thank you from me for this wonderful article.It's exactly these kind of stories that I hope to find here every morning when I start the day.
JimmiG - Sunday, February 14, 2010 - link
Well the late changes would explain why the RV870 isn't "perfect" like the 770 was. At every price point except at the high-end, it delivers more features, but less or similar performance as the previous generation. For example the 5770 is slower than the 4870, the 5750 is about the same speed and price as the 4850 and so on. Also at the high-end it's more expensive than the 4800-series ever were - the 4870 was only $299 at launch, the 5870 is still at least $399. By this month in 2009, the 4870 was down to $249!