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AMD and Intel Update CPU Roadmaps
vincecate writes "Recently
AMD updated their processor roadmap. It shows their move to 90 nm and has a range of new processors over the next 1.5 years, including dual-core chips. An
unofficial AMD roadmap shows speeds and performance increasing.
Intel also recently updated their roadmap.
Intel does not show anything faster than
the current 3.6 Ghz in the next 11 months, including the recently delayed 4 Ghz chip, except to say '3.6 Ghz or greater.' Strangely, some of the recent SPEC benchmark results show the 3.6 Ghz chip to be slower than the 3.4 Ghz chip. One possible explanation for this is that the 3.6 Ghz chips will slow down due to 'thermal throttling' if you are not very careful to keep them cool. So it seems like heat may be the reason Intel's roadmap does now show much improvement."
The reason the 3.6GHz processor runs slower than the 3.4GHz processor is because they're different processors, not the same processor running at different clockspeeds. Just look at the die photos (www.chiparchitect.com) and you'll see what I mean. The idea is that the new processor will scale to higher clockspeeds which it, uh, already has. (Just look at the "OC records": nobody got an old Pentium 4 beyond 4GHz with standard HSF cooling - nobody. On the other hand, this is more or less straightforward with the new Pentium 4s.
What I don't understand is why more people aren't building Pentium M desktops.
Actually, during a review session with the 3.6GHz LGA775, we experienced so high heat production that we had to use water cooling to ensure that the thermal throttling was not enabled. When using regular air cooling the processor would reach temperatures > 70 degrees during load, and from the results at this load we saw that at some times the processor had to use thermal throttling.
Another disadvantage with this high heat production is that other core components in the computer (such as the mainboard) will be exposed to more heat as well, hence the durability of these components will be lower.
If Intel and AMD continues to approach Itaniums heat production, water-cooling or similiar technologies will become mandatory for high end processors.
Last week I benchmarked the 2.2Ghz Opteron on 64 bit Linux 2.6 and Java. I got almost three times the performance of a 3Ghz Xeon. For details see http://gregluck.com/blog/space/start/2004-07-29/1# AMD64,_JDK1.5.0_and_Linux_2.6_rock!/
In addition to this, until we start seeing widespread use of PCIe, the downstream AGP bus is still a serious bottleneck as well. Uploading data to the GPU is really fast, downloading maxes out at ~133MB/s.
I haven't had the chance to play with a Pixel Shader 3.0 card yet, so I don't know how useful for generic computation they are. It usually helps if you're trying to process many sets of the same kind of data, rather than evolving one calculation through a long or iterative algorithm.
~phil
You can have those, just not at the same time. Via Eden runs fanless. But it's still 32bit! And it doesn't run in SMP-configurations (yet. there has been some info about SMP-solutions).
I think you could buy an Opteron 2xx-machine, underclock it to around 1GHz so it might run fanless. Then you would have your fanless 64bit SMP-machine,
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I was talking to my friend about this the other day, and we think that eventually they cannot go that much faster (well, maybe have a SMALL core of the chip that can go faster), and they'll start stacking in parallel instead. Ie, massively hyperthreaded processor cores. So maybe in a few years we'll see 6 GHz chips with 8 or 16 hyperthreaded processors?
We're physicists, though, not engineers, maybe there are some other clever ways to keep pushing the envelope?
make world, not war
FYI - I have an Athlon 64 and heat hasn't been a problem at all. I just have the retail processor with the el-cheapo heatsink that it comes with (nothing fancy - just thermal compound and a reasonably-sized sink). I haven't seen it exceed 55C under heavy load. Granted, my case is fairly well-ventilated, but nothing excessive (well, the case was excessive, but I unplugged about half the fans). Oh, did I mention that I overclocked it by about 8% or so?
AMD used to have a high-heat reputation and used to be known for difficult-to-overclock processors. Honestly, I don't think that is nearly as much the case with their newer processors. The Athlon64 seems to run fairly cool, plus it supports frequency scaling when it isn't busy (note - the 55C figure I gave was under heavy load for considerable time - no scaling in effect). Right now, I'm typing on the machine and the CPU is reading 37C - only 1.5C higher than case temperature.
I think AMD is actually passing Intel in this respect. Intel had better watch out if they expect year-long delays - eventually AMD will be releasing 3-4GHz Athlon 64's and they'll be FAR faster than anything Intel currently has...
That's the problem Intel has right now, really. Marketing seems to say, "Make it sound faster", only looking for good warrior CPUs in the Mega Hertz Wars. IBM/Apple and AMD have not been trying to go for faster clock speeds but instead for faster CPUs.
Such long pipelines as the Prescott line may help achieving higher clock speeds, but 31 stages means that you'll see more pipeline stalls, so your CPU is happily running at higher clock rates, doing nothing. Of course, not all instructions actually have to go through all 31 stages, but still, it's impractical to have so many stages in an architecture when you know that every so-many-but-fewer-than-31 instructions you're going to hit a branch. Not to mention the additional complication for the on-die dependency tracking that you need in out-of-order cores like Prescott.
Of course in-order architectures with full predication ISAs would solve some of the problems with longer pipelines, but I guess we can't say that this other Intel architecture, ia64, is such a great success ;-)