i3 & p55c

I think Intel is usually the winner here. Pentium III (Coppermine especially) had a lower TDP than the AMD Athlons. Don't know about their earlier CPUs as I've never really looked at their performance and TDP.

Today Intel Core has a lower TDP than the AMD FX series. I think the AMD APUs can be more or less the same as the comparable Intel CPUs tho.

For modern systems, the Core i* S and T series are probably the performance-per-watt winners. They're 65W and 35W variants of the 80-90W "normal" chips. They don't come unlocked and have lower "nominal" clocks, but the boost clocks are generally the same as the "normal" counterparts. They also tend to cost a little more. If you're going to use integrated graphics, however, the better AMD APUs offer generally higher performance than the Intel chips, and are in a similar 80-90W TDP range, so they'd be a better choice there. Price-wise and power-wise you may still be better off with an entry-level GeForce or Radeon card and low power CPU though.

For older systems, the Pentium 3 as has been mentioned, the AthlonXP-M (M for Mobile), and Pentium M were all good candidates for low TDP performance.

Something else to keep in mind: CPUs will not consume 100% of their rated TDP all the time. For example I have a system with a Pentium 4 EE, which has a stated TDP of something like 104W, and the entire machine will idle on around 80W AC (so the DC draw is even lower than that). Loading draw is higher (maybe double), but it's generally not so bad power-wise for something that isn't turned on very often, and that doesn't run intensive applications 24x7.

TDP vs Performance wise, P4 shouldn't even be mentioned 🤣

smeezekitty wrote:

TDP vs Performance wise, P4 shouldn't even be mentioned 🤣

🙄 The point was not to suggest the Pentium 4, only to use it as an illustrative example. Lower power hardware will follow the same trends, although older PSUs tend to be horribly inefficient, to the point that newer systems (like P4, A64, etc; basically that can play nice with modern ATX 12V-heavy PSUs) may end up using less power overall due to the more efficient PSUs available. This is actually the case with my Dell 4100 vs the aforementioned P4EE system. While the CuMine P3 technically uses less power, runs cooler, etc the inefficiency of the Dell PSU means that, at the wall, the system uses as much power as the faster P4. Of course a newer PSU would advantage the P3 as well. Just food for thought if power efficiency is actually the goal. If a lower-power CPU is desirable due to improved cooling (low temps + low noise), that's another discussion - while something like Pentium M can produce a very quiet machine, so can more conventional desktop chips with the right setup.

I was researching for a new build and remembered my "silent pc" phase back in the early 2000's. Started browsing for this and ended up reading about tdp. Actually I'm pretty happy with a 45W tdp nowadays, but still I was curious about your opinion. I became amazed with some designs like the i7 4610y at just 11.5W or the Atom Z500 with under a watt! Pentium 4 is in a league of its own, yes, but that does not stop us from thinking about it right? What would be the best Pentium 4 performance per watt wise, for instance.
The first copermines , like the 500MHz version do look very good at 16W.

the newer the better in general, except for the pentium4s which were a huge step backwards.
in the 90's, i would say that pentium3 with coppermine core is the best.

In the 90's there were several CPUs that did better in that respect and several others that did worse.
Pentium 1 (including MMX) was quite efficient, better that Cyrix or AMD K5/K6. K6-2 (and later K6) did better because they used 2.2V, but the faster speed grades will also use more power without being too fast because they are limited by the FSB. K6-3 was fast but also rather hot, K6-2+ and K6-3+ were better but the difference between typical and maximum power usage is not as big as with Pentiums. K6-3+ 400 ATZ is very nice, that one uses only 1.6V. (I'm not sure what typical power usage exactly means here, I guess it is still 100% CPU load.)
For P3 Coppermine does indeed well, especially the slower ones. The faster ones also use more power, Tualatins are better in comparison, though AFAIR those don't save much power when idle as opposed to Coppermines. P2's are not very efficient, but of course Deschutes still does better that Klamath.

After that you'd have to wait until Pentium-M.

Low end coppermines are pretty awesome for low power usage in some simple task that they're suited for. Any systems I've measured using a Deschutes, Tualatin, Athlons, or need I even say P4, have all been more power hungry.
A highly integrated (i810?) board with a low end coppermine and small PSU drew about 25W from the wall in Windows. Even an EATX server board that I've measured with a much bigger PSU still only idles in the 40s.
A 1.4Ghz/512KB Tualatin I tried was surprisingly high power at idle. Maybe lower end Tualatins are better.

Coppermines might not be as good in terms of the (performance / power) arithmetic, but the way I look at it, all that really matters is whether it's fast enough to do what it needs to do. If it's an app where you need all the performance you can get, then obviously an old CPU like the Coppermine would be immediately ruled out.

TELEPACMAN wrote:

I was researching for a new build and remembered my "silent pc" phase back in the early 2000's. Started browsing for this and ended up reading about tdp. Actually I'm pretty happy with a 45W tdp nowadays, but still I was curious about your opinion. I became amazed with some designs like the i7 4610y at just 11.5W or the Atom Z500 with under a watt! Pentium 4 is in a league of its own, yes, but that does not stop us from thinking about it right? What would be the best Pentium 4 performance per watt wise, for instance.
The first copermines , like the 500MHz version do look very good at 16W.

My "silent computer" (it is not 100% silent - it still has mechanical drives, faintly audible coil whine/relays (with the case on these are almost impossible to hear if you don't know about them), and very quiet cooling fans (which are not always on), hence the quotes) is actually the EE mentioned earlier (there are pictures in the Retro PC thread). It's probably not very efficient, in terms of using 70-140W of power, but it is very quiet. I built it mostly to see if it could be done with a P4, and it worked out nicely IMO.

For absolute efficiency, any of the newer embedded stuff for Ultrabooks is probably going to run away with the show. Atom, C7, etc that use very low power also usually have very low relative performance ("in their day"). Depending on what the machine has to do, that may or may not be a problem - years ago when I had a Netbook, the Atom's low performance wasn't an issue. But that machine cannot handle modern multimedia content and some applications that my Ultrabook with its ULV i5 can power right through. Power consumption between the two machines is fairly similar too.

For desktop machines, there are 30-50W CPUs available. You can also look at some of the more integrated ITX/mATX platforms that use Celerons, AMD APUs, etc and don't draw very much power. The bigger thing to consider with desktops these days is the graphics card - a top of the line Intel CPU is only around 100W TDP, which can be quietly managed with a good heatsink, but most top of the line graphics cards can draw 2-3x that under heavy load, and many of them use blowers to cool themselves. Mid-range graphics cards seem to be the sweet-spot for inheriting power management features from their titanic big brothers, without the big power draw/heat. The GeForce GTX 750 and Radeon R7 250 are good examples of this. This isn't to say high-end graphics cards must be loud; my 290X has an OEM cooler that keeps it fairly quiet, but it isn't silent. Much better than what we had just a few years ago though (it is much quieter than my HD 4800 series cards, for example).

Older systems tend not to have such power-hungry GPUs. A CuMine paired with a GeForce MX or Radeon 9550/9600 can be very quiet even when gaming, and isn't very power hungry either. Other stuff to consider for older machines: optical drives, hard-drives, diskette drives, small fans, etc. All of those usually bring in noise. On my quiet box, the optical drive is the loudest component, and I'm using the quietest DVD drive I've ever found. IME once you get past noisy CPU coolers and high-RPM case fans, all of the "other" stuff starts being the big problem for noise.

WRT the best P4 for performance-per-watt, either the Cedar Mill 65nm chips, the Gallatin-based Extreme Edition chips, or the early Northwood chips. The "rub" here is that you can usually replace an early Northwood with a P3, and a Cedar Mill or Gallatin with a Core 2 or Pentium M, all of which will use less power on average.

@obobskivich:

Can you tell me what that 'silent' dvd drive is - i am looking for one since .... ever (and didn't find anything matching).

Topic:
I think to find an answer is almost impossible: Without specifying the purpose a cpu is used for and of course the generation you want it to be part of you only can exclude some bad ones (like the p4 or maybe something like Cyrix 6x86 (although i like the Cyrix!)). Try to compare a 386 with a PIII and the former will give you a much worse TDP/Perf. ratio as the latter will. The newer a design and a production process of a cpu, the better (except P4!) the TDP/Perf. will be.
For me in terms of retro-computing the Tualatin, the 2.2 V K6's, the P55C and the Deschutes are examples of CPU's with good TDP/Perf. ratio.

popper wrote:

@obobskivich:

Can you tell me what that 'silent' dvd drive is - i am looking for one since .... ever (and didn't find anything matching).

It says "MagicSpin" on the label, and doesn't have much else information. It's PATA, white/beige, and very quiet. I haven't taken it entirely apart to see if there's damping internally, but the tray is gasketed to the body to reduce vibration and noise, and you barely hear it running. Much better than typical Lite-On screamers, or even the Plextor and Toshiba drives in my other systems.

I do not remember where I purchased it, but it was sometime around 2003. Sorry I don't have more info. 😊

EDIT: A quick look on ebay for "MagicSpin" and there are a number of options available - some are even burners. I'm not sure if any of them would be as quiet as mine or not; I don't know if the brand made its own drives, or is simply a re-badging of OEM'd drives. If that were the case, it's possible some come from a "quiet OEM" and another from a "loud OEM" if that makes sense.

There is always the QuieTrack series from Asus, that's what I used to have. It works. Silently.

obobskivich wrote:

smeezekitty wrote:

TDP vs Performance wise, P4 shouldn't even be mentioned 🤣

🙄 The point was not to suggest the Pentium 4, only to use it as an illustrative example. Lower power hardware will follow the same trends, although older PSUs tend to be horribly inefficient, to the point that newer systems (like P4, A64, etc; basically that can play nice with modern ATX 12V-heavy PSUs) may end up using less power overall due to the more efficient PSUs available. This is actually the case with my Dell 4100 vs the aforementioned P4EE system. While the CuMine P3 technically uses less power, runs cooler, etc the inefficiency of the Dell PSU means that, at the wall, the system uses as much power as the faster P4. Of course a newer PSU would advantage the P3 as well. Just food for thought if power efficiency is actually the goal. If a lower-power CPU is desirable due to improved cooling (low temps + low noise), that's another discussion - while something like Pentium M can produce a very quiet machine, so can more conventional desktop chips with the right setup.

Ah yes, now is time to mention the 3.8 Ghz Prescott @ 115 watts. Overclock that sucker to 4 Ghz and you have one 'highly clocked core'. Joking aside, it's retired as a 'bench' machine (used to be my main, but it's not 2005 anymore).

Northies aren't too bad for power consumption, in fact gross early slot 1 P3s can consume more TDP than your early northie.
P4 SL62S @ 1.6 Ghz at 38 watts [vs] P3 SL3JU @ 600 Mhz at 42.76 watts

Of course Tualatin @ 1.4 Ghz with 32.2 watts is probably the choicest, but the FSB is considerably less than the northie.

QuieTracks are pretty good, get an 8x Nakamichi if you want a quiet CD-ROM drive. Soon as you go past 12x drives start to get noisy.

Thanks for all the advice on the dvd drive....

Of course Tualatin @ 1.4 Ghz with 32.2 watts is probably the choicest, but the FSB is considerably less than the northie.

Higher FSB doesn't help much if the core can't keep up with it.

popper wrote:

Thanks for all the advice on the dvd drive....

You do know that there are slowdown utilities for CD/DVD drivers which will make the drive less noisy? (Both for Windows and DOS.)

https://ark.intel.com/products/27425/Intel-Pe … FSB?wapkw=sl62s

Are these special P4-CPU's available? Does someone have such a CPU? (SL62S)
If it was an OEM only Produkt, does anyone know, which manufactors used this special cpu.

I would really like to have such a CPU in on of my FSC-Desktops because the next best downgrade was the king (1400 Tualatin).

Thx
Doc