Engineers: 89W to 65 ~ Horsepower Drop?

[Carson]

I'm interested to find out what happened to AMD's 64x2 5200+, specifically, when the Windsor core was modified from F2 revision to F3 revision.

Staying with L2 caches of 2 x 1024KB, and staying with 90nm SOI, the voltage was dropped a wee bit from 1.30/1.35 to 1.20/1.25.

But the real difference was in the wattage, which was reduced from 89 to 65.

Actually the Windsor tests very well at Cool 'n' Quiet beside the more recent Brisbane, although the Brisbane is the popular favourite. However, I prefer the Windsor for its ability to access better performance at full tilt.

But my question is, does 65 watts translate into less horsepower than 89 watts? I'd like to get the 65 watt version for its assumed better power efficiency. Or would I regret my choice? In the (very crude) anology of vehicle horsepower, an underpowered car can be less efficient than a car with more horsepower. Well, computers aren't cars, but just what DID happen to the 5200+'s performance when AMD modified it to 65 watts?

Thank you very much for your insight.

[Babrbarossa]

I'm no engineer but I`ll go out on a limb and say that the difference is that the transistors are smaller and the structures use less voltage so there is less power consumption for each switch event so theoretically there is no difference. But as the process shrinks, the need for greater and greater precision in the manufacture of the components makes it harder and harder to stay within acceptable tolerance limits which can lead greater potential for errors or instability reducing overclocking potential. This potential for instability ias somewhat counteracted by reduced heat from the lower power consumption but not entirely. From what I have read, the 89W chips do in fact overclock a little better but I don`t know how true it actually is.

[Carson]

Thank you, Babrbarossa. Pretty darned good answer, I'd say, engineer or not.
Hmmm. . . good enough that I'm now a bit perplexed. Well, let's see. . . .

My AMD 64 x2 shortlist includes versions with L2 = 1024 x 2, and nothing @ 125 watts. On the low side, that eliminates the Brisbanes (L2 = 512 x 2), and on the high side it eliminates the 6000+ and 6400+ (125 watts).

— AMD 64 x2 5200+ Windsor revF3 EE (Energy Efficient) @ 65 watts; core speed 2600
(my choice here is based on maximum power in this series available @ 65 watts)

— AMD 64 x2 5200+ Windsor revF2 @ 89 watts; core speed = 2600 MHz
(seems a waste of power, but if it has better performance, then maybe)

— AMD 64 x2 5600+ Windsor revF3 @ 89 watts; core speed = 2800 MHz
(If I went up to 89 watts anyway, then maybe I'd be better to get this; although I think it might run hotter. I'd like cool as possible, and reasonably energy efficient.)

I want a really steady system that can perform very heavy multitasking without even wincing. I'm pretty close to my preferences on these CPUs, although I'm darned if I know which one I'll choose.

I want a lot of good RAM, probably 8 GB (I'm OK about buying RAM a bit into the future, and my OS will be XP x64 (maybe Vista x64, but I don't like Vista). I'd like an mb that can take even more RAM, as some of the Gigabyte mbs can. Looks like DDR2-800, I suppose.

It's for heavy usage and constant reliability, and I want excellent speed with a ton of photos up to astronomy-size. No gaming, though. I want to avoid heat and I want to keep electrical use low. I'm hoping to add a 22" LCD.

I thought I'd toss that out in case anybody thinks he knows a very nice
motherboard —I'm thinking of maybe a Gigabyte GA-MA790FX-DS5—
or
video/graphics card.

Or if you have any of those CPUs, it would be great to hear from you.

Thanks again, Babrbarossa.

[Babrbarossa]

What are your constraints here? ie- AMD only, dual core only, low budget, gaming requirments, etc. Are you building from scratch? If you're really looking for multitasking, you might want to get a quad core.

I'd say you're better off buying something more cutting-edge with only 2 or 4 GB of ram than buying an older process and 10GB of ram.

[Carson]

— AMD only
— low budget; something like $700 without a monitor (+ $300 for a 22" LCD). No OS or software required; this is just hardware. (I'm intending to run XP x64.)
— dual core or quad (quad would be nice but might be too costly)
— no gaming, but I don't want to mislead anyone: I do a lot of multitasking, a lot of graphics, and I do need a LOT of power and speed
— building from scratch but I'm hoping to use whatever I can from the old system, where possible

I'd say you're better off buying something more cutting-edge with only 2 or 4 GB of ram than buying an older process and 10GB of ram.

Well, your advice is pointing toward a quad-core for sure, and I'd be happy with one. I think I'm too early for AMD's efforts, though. I was thinking the 64 x2 series were very good systems with good speed, which would fit into my budget. I wouldn't buy a 3-core Phenom, nor a Phenom with a minus-15% bug. (In fact I think a lot of people wouldn't, and I'm afraid AMD might be seriously damaging its name—this although I really like AMD.)

So I need more time and more money. Hmm. I think I've stood in this place before.

[Babrbarossa]

I think the triple cores are going to be decent processors- we'll see how cheaply they're priced though. They're supposed to be out in march(ish)

A blurb from TPU:
As most of us know, AMD was hoping to shove the triple core Phenom series (8x00) out their factory doors by next month. However, it would seem as though things have changed over at AMD. The Phenom 8400 (2.1GHz) and 8600 (2.3GHz) will both be launched at CeBIT 2008 (which will be hosted in early March). However, AMD may ditch the 8700 in favor of a B3 stepping 8750, accompanied by an 8450 and 8550 from the same stepping.

Any processor from the B3 stepping should fix up the hated TLB issue that early Phenom processors suffer. This B3 stepping will also show up in quad core parts. The Phenom 9700 (2.4GHz) and 9900 (2.6GHz) will be replaced by the B3 based 9750 and 9950, respectively.

[Carson]

Well, I would be interested in a Phenom 9550 if that's what they call the 3rd stepping, as your article says. They just might release it fairly close to the 9500's price.

I think AMD has a good market in notebooks. But these desktop debacles are scary even just to read about. Imagine releasing ANYthing onto the market with 1/4 of its intended function disabled—because it didn't quite work. And then to ADD to that acknowledgment of a bug that has, as its workaround, disabling one of the main functions [in this case the L-3 cache] the company has been touting. And THEN to say, "Well, it doesn't really matter much—it's only about 15%".

The L-3 doesn't matter much? And 15% of the performance isn't significant?

I think that would be very, very dangerous marketing even if AMD were in the business solo. But add to that Intel, with a much bigger budget and a real hunger for a monopoly, and the whole game is like television fiction. AMD: Alive Mainly by Determination.

[Babrbarossa]

well if you're unhappy with AMD's product, you can always go for the better price/performance ratio and just buy intel- after all, every company seeks greater market share and AMD doesn't know or care who the hell you are