Hi Seni,

Seni (seniike@hotmail.com) on 2/11/11 wrote:
---------------------------
>>>>So instead of a multi-core CPU with an IGP you might as well have a CPU with a couple more cores.
>>>
>>>I'm wondering why you think there is a viable market segment that is too cheap
>>>to pay $5 for an IGP and yet wants more cores.
>>>Outside of the server market, some workstations, and a few other niches, the extra cores are not all that useful.
>>>And the things they work for are things that GPUs do too - media transcoding, offline rendering, games, etc.
>>>Why would someone who wants no GPU want more cores?
>>
>>First of all, an IGP does not cost 5 $. A quad-core Sandy Bridge costs at least
>>177 $ and the IGP takes 18% of die space. That's over 30 $.
>>
>
>You can't just divide and get the cost like that. The actual cost of the die area
>is quite small - around $20 for the entire Sandy Bridge chip. The rest of the cost goes to:
>- cost of the fab
>- package/pins
>- testing/binning
>- cost of the process R&D
>- cost of the chip design
>- cost of validation & verification
>- cost of the mask set
>- cost of writing drivers
>- cost of marketing programs
>- and so on.

If this was a valid argument then a Core i3 would cost only 5$ less than a Core i7. Clearly things like testing/binning, R&D/design/validation/verification, mask set and drivers also affect the IGP cost.

Comparing the area really isn't a bad approximation of the real cost. In fact is should be higher since it's entirely different testing/binning and R&D/design/validation/verification compared to just varying the number of CPU cores.

>The cost of the die area for the IGP really is about $5. But compared to the way
>they did it before, moving the IGP onto the CPU probably saves more than $5, so really it's free.

Making one thing a little cheaper doesn't mean some other expensive part suddenly became free. The total cost for the IGP is a lot higher than the ~5$ of the chip cost alone, and you can save a significant part of this total cost. A 6-core CPU would be cheaper than a quad-core with IGP.

>If they did it your way and didn't design an IGP at all, they could save both the $5 and that last little bit of R&D...
>Except that instead of spending money on IGP design, they have to spend it on software renderer design.

How many developers do you think it takes to write a software renderer? Pixomatic was written by two people. Now compare that to the number of specialized people you need to perform all of the above described tasks to get an IGP onto the CPU.

Note that a big strength of the move to software processing is that there are millions of software developers *eager* to develop for powerful homogenous chips. There's no significant difference in cost to design a game for the GPU versus the CPU. In fact today a great deal of time is wasted trying to figure out how to get the GPU to do what you want. Note that taking detours also results in lower effective performance.

So in the long run what you'd get with a homogenous CPU with FMA and gather/scatter is a highly competitive software ecosystem with lots of new exciting products, at a lower cost to the end user. No need to pay Intel for something you migth not use much. Instead, you get more powerful hardware for your money.

>>Secondly, not having an IGP doesn't have to mean replacing it with CPU cores. You
>>can also opt to save 30 $ and still enjoy having a fast CPU which can adequately
>>take care of 3D graphics should you need it.
>
>A cheap CPU wouldn't be adequate for texture filtering even if it had 2 more cores.

Yes it would. The HD Graphics 3000 IGP has just 2 samplers. A 6-core CPU with FMA and gather/scatter would be like having up to 12 slightly slower samplers.

Note also that while the IGPs samplers can be either a bottleneck or running idle, a unified design can achieve higher peak throughput and only pays for delivered throughput.

>>Last but not least, people who use a discrete graphics would much rather have a
>>6-core CPU with gather/scatter than a 4-core CPU + IGP.
>
>The people who would want to trade away the IGP for two extra cores, they already
>can. There is a separate product for them - namely 6-core Gulftown.

Gulftown doesn't have AVX, and requires a socket 1366 motherboard. So Gulftown sales are not a useful representation of the market for a future homogenous CPU with FMA and gather/scatter.

>>>Other than misinformed consumers, I expect that market hole is awfully small.
>>>Generally, consumers either need graphics for gaming, or need neither graphics
>>>nor cpu power and would be better off with a netbook-class processor.
>>>The consumer who buys an eight-core processor to browse the web is a fool.
>>
>>If that were a valid argument, then there would also be an awfully small market
>>for Sandy Bridge as-is.
>
>Well, firstly, there are many misinformed consumers.

That's true for any product. Most consumers will buy a bigger car than what they actually need for daily commutes. So call it misinformation or whatever, people will buy the system with the highest performance for the money, even if they could do with a little less performance most of the time.

They're still getting a more compelling system. In particular, it should be more future proof. History shows that software developers have always come up with ways to push the hardware requirements up. The Althon X2 I once paid 500€ for, is now a real pain to work on. And my 2500€ laptop with a Core 2 Duo 2.0 GHz is overdue for a replacement. And mark my words, multi-core software development is only at its infancy. A 6-core CPU is going to look average in just several years time.

>Others think before they buy the computer that they will never play games on it.
>Then they change their minds after it is too late.

It's exactly the same for the CPU. Most still buy a dual-core CPU, based solely on the fact that most applications don't take advantage of more cores just yet. But they're not taking into account that the software world moves relatively fast and they're best off planning ahead 3-5 years.

That said, for a desktop system it's never too late to change your mind about gaming performance. You can start with a 6-core CPU performing graphics in software, and when it turns out you do play more games than anticipated, you can buy a discrete graphics card. If instead you started with a CPU+IGP, you'd have wasted money on the IGP. And if you need more CPU power, the CPU+IGP solution requires you to upgrade sooner.

>>Noone who calls himself a gamer is going to buy a Sandy
>>Bridge CPU and use the IGP.
>
>You might think an IGP would be useless to someone with a proper GPU. It's not.
>
>I bought a laptop in 2008 or so, with a Penryn 6M and a Geforce 8800M. It also has an IGP.
>It offers a low-power mode that is useful when you don't want to waste power using the real GPU.

That's again something you can get from a homogenous CPU as well. When not running games, the near-idle power consumption of a modern CPU is lower than that of a hefty GPU. And if that changes in future designs due to better power gating in the discrete GPU, you still got a more powerful CPU while the IGP became useless. Honestly, falling back to the IGP because the GPU takes too much power at low load isn't a feat of the IGP but poor power management of the GPU. There's no reason it shouldn't be able to shut off partially instead of entirely to achieve a good balance. So using the IGP instead is just a short-lived band-aid.

I'm happy for you your setup gives you a pracical advantage for the current reality, but it's not a long-term argument pro IGPs.

>More importantly it's a backup in case the Geforce dies. Which in fact, it did.
>So now I use the IGP. If not for the IGP, the system would be unbootable until
>I got a replacement GPU, which for laptops is a huge pain.
>Am I glad I spent the extra $5 to get an IGP? Hell yes!

With all due respect that's just a silly argument. It only shows how unreliable GPUs really are. Would you buy a car that comes with a free bike, "in case it breaks down"? Personally I'd rather buy from a manufacturer who gives me a higher quality guarantee. And note this 'bike' isn't actually free.

Seriously, IGP+GPU systems have no future.

>>>Non-consumers are different, as they have non-graphics servers, and non-graphics workstations.
>>>But there are separate processor lines for servers and whatnot, so they don't really count here.
>>
>>It does count for something because designing an IGP has a high R&D cost. In other
>>words a 6-core CPU can be cheaper than a 4-core CPU + IGP even if the die size is
>>exactly the same. Furthermore, having different production lines and testing methods
>>and all that reduces the efficiency so not having to produce CPUs with an IGP not
>>only saves R&D but also production cost.
>
>Having multiple products is necessary anyway (2-core netbook vs. 4-core laptop
>vs. 6-core workstation vs. 8-core server)
>The R&D cost can't be reduced unless they completely eliminate all IGPs from their entire product line, including Atom.

Yes, multiple products remain necessary, but not another combination of CPUs with and without IGP. Reducing the number of product lines, reduces cost per part.

And you appear to imply that Atom uses the same IGP design as Sandy Bridge. That's incorrect. Pineview has a GMA 3150, which is the old Direct3D 9 generation GMA 3100 shrunk to 45 nm. It does vertex processing in software! If all desktop CPUs eliminate the IGP and several years later Atom runs out of IGPs to shrink down, Intel can still license cheap IGPs from PowerVR. The cost is lower than designing such an IGP in-house since the PowerVR design is licensed to multiple manufacturers. And it's definitely cheaper than continuing to design IGPs suited for the desktop market.

So once again ditching the IGP saves money, which translates into more valuable homogenous CPUs for everyone.

Regards,

Nicolas