AMD's 65nm Preview Part 2 - The Plot Thickens (Updated with Information from AMD)
by Anand Lal Shimpi on December 21, 2006 12:12 AM EST- Posted in
- CPUs
Final Words
Now that the pieces are falling into place we are able to understand a bit more about the implications of AMD's move to 65nm. It's clear that these first 65nm chips, while lower power than their 90nm counterparts, aren't very good even by AMD's standards. Already weighing in at the high end of the voltage spectrum, we hope to see more overclockable, lower power offerings once AMD's 65nm ramp really starts up. It's a constantly evolving process and if this is the worst we will see, it's not terrible; AMD can only go up from here, but it does mean that you shouldn't hold your breath waiting for the right 65nm AMD to come along.
Performance and efficiency are still both Intel's fortes thanks to its Core 2 lineup, and honestly the only reason to consider Brisbane is if you currently have a Socket-AM2 motherboard. It is worth mentioning that AMD still has the lowest overall power use with its Athlon 64 X2 EE SFF processor, but in terms of performance per watt efficiency it's not all that great. We would really like to see an EE SFF successor built on AMD's 65nm process, but we have a feeling it will be a little while before we are graced with such a delicate creature.
The step back in performance with Brisbane is truly puzzling; while none of our individual application benchmarks showed a tremendous loss in performance, it's a very unusual move for AMD. The last thing AMD needs to do is take away performance, and based on its current roadmaps the higher latency L2 cache makes no sense at all. Either AMD has some larger L2 cache variants in the works that we're not aware of, or AMD's cache didn't take very kindly to the 65nm shrink. As soon as we get the official word as to why L2 access latencies jumped 66% with Brisbane we'll be sure to report it; until then we can only wonder.
We long for the good old days, when a die shrink meant ridiculously overclockable processors, back before a die shrink was coupled with a sneaky decrease in performance. While Brisbane is far from a Prescott, it's not exactly what we were hoping for from AMD's first 65nm Athlon 64 X2. Hopefully they can work out some of the process' kinks in time for the K8L launch.
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Spoelie - Thursday, December 21, 2006 - link
This is not the first time this has happened, it may be easy to forget, but do you guys remember the thoroughbred?Thoroughbred A was the first 180nm to 130nm shrink and had a hard time reaching the speeds the mature 180nm cores were getting. It wasn't till AMD added another layer to the core (Thoroughbred B) that we saw the expected speedups from a die shrink.
PetNorth - Thursday, December 21, 2006 - link
Anand:Why don't you set manually the voltage, to know really what's the improvement with 0.65 transition?
1.30v to compare it with 5000+ 90nm, and 1.25v to compare it with 4600+ EE 0.90nm.
It would be a good thing IMO.
yyrkoon - Thursday, December 21, 2006 - link
There are already people who believe that odd numbered multipliers offer worse performance compared to even numbered multipliers. I cant help but wonder why AMD chose to start implementing floating point multipliers now. The first thing that comes to mind, is maybe to refine their pricing ? Although, I've never really noticed much performance (if any) difference using odd vs even numbered multipliers, I can not help but wonder if floating point multipliers will play a factor in performance.Regs - Thursday, December 21, 2006 - link
AMD has been stepping in baby steps in their innovation merits. Ever since the IMC and the enhancements from K7 to K8 it seems like they improve little by little. I hope this gives them a rude awakening to how competitive the market can or could be in future. If they did it before they can do it again.As for the transition to 65nm, it was no surprise that these parts could not over clock very well. The K8 is showing its age and I think there are no more ways you can breathe life back into it especially when Core Duo is out in the market.
mino - Thursday, December 21, 2006 - link
Why awekening, and why rude? The fact is AMD kept PARITY with intel on power AND performance inthe lower end with 90nm!!! part with Intel beeing at 65nm for a year allredy!In other words, When AMD's 90nm process is FAR better that Intel's ever was. Same happened with 130nm. Two words: SOI,APM.
No confusion, all thi means no one should avaluate AMD vs. Intel on process_used base. Simply put, as of now(at stock) Intel rules on perf&power while AMD rules on idle_power and price(up to 4200+/E6300 combo).
IntelUser2000 - Thursday, December 21, 2006 - link
Intel bins Core 2 Duo by power consumption.
xsilver - Thursday, December 21, 2006 - link
just to clarify further; all e6600's will have lower stock voltages than e6400's and all e6400's will have lower stock voltages than e6300's?at both idle and load?
how successful are the conroes at undervolting?
Accord99 - Thursday, December 21, 2006 - link
Pretty good, my week 25 E6600 is stable at 2.6GHz/1.1v (My P5B-dlx doesn't go any lower) with dual-P95. The heat output is easily cooled passively by a Scythe Ninja.Here's a thread, one person has a E6600 that does 2.4@/~1v
http://www.xtremesystems.org/forums/showthread.php...">http://www.xtremesystems.org/forums/showthread.php...
blackbrrd - Thursday, December 21, 2006 - link
I have seen a E6600 running at 1,0v at load... It was obviously very cool running :)My E6400 is running at 1,15v at idle (2133MHz) and 1,25v at load (2133MHz)
Power saving features were off in both instances...
haugland - Thursday, December 21, 2006 - link
AMD win in one aspect...I you really consider power consumption to be important, it is much more important to look at idle power consumption than power consumption at full load. Most business PCs idle a lot of the time, and AMDs CPUs are much better at saving power at idle.
EIST was designed for P4, and for a 3+ GHz P4 it makes sense to drop the multiplier to 6. However when the E6300 normally run at a multiplier of 7, you don't get much of a power saving by dropping the multiplier to 6. AMD C'n'Q allows for much lower settings.