Power efficiency focused builds - What are the options?

[PixelButts]

This is a speculative thread, and it might be boring it might not, so I'll get straight to the point.

The idea of building a power efficient, yet high performing PC has been on the mind lately as my power bill is getting silly and I'd like to explore this a little bit. It's easy to just say "go get a <cpu> and put it with <whatever gpu you got> and you'll be fine", but what about a scenario where you're wanting the absolute most out of some lower-power parts? Once that headline of the 9070 XT being undervolted and matching a 5080 in some scenarios it got me wondering a little bit about a build geared to do just that. Similar to the guy who shunt modded his 7900 XTX and dumpstered a 4090, though it drew identical wattage.

The general goal criteria would be as follows

1. CPU with lowest wattage with highest performance offerings (which seems to be 7600X3D at the moment? Here's hoping for a 9600X3D)
2. GPU with the most undervolting and overclocking capability
3. No extra power wasting (as few fans as possible, no RGB, etc)
4. Making the most out of it under load is the focus, idle draw isn't really a concern
5. Price doesn't necessarily need to matter but ideally lower is better
6. Size constraints are not required to be anything specific, go wild
7. If using a Mini PC form factor, is there a setup that can out perform a full desktop solution under the above constraints? (Oculink, eGPU of any capacity)

Current offerings tells me X3D is easily a winner there for CPU, GPU would be a hard one to determine, RAM might be a hard one to measure but may be negligible but due to overclocking and timings may increase power draw, HDDs are out but NVME drives are in. Mini PCs are clearly the easy answer but their choices are somewhat limited as iGPUs only go so far.

I usually don't like to make speculative threads on any forum, but this one has been bugging me since I don't really see too much discussion beyond a little undervolt there a tiny overclock there or just running stock.
I have several setups that I'm considering changing in a number of ways, some with specific tasks, some with a singular very annoying task, and it's starting to annoy me how much electricity I'm drawing with my current setup, so that's the primary motivation here.

 

[AusWolf]

What do you want it to be efficient in? Games? Rendering? Other type of work? Or at idle / light browsing / media playback? There are too many criteria to choose with.

 

[JustBenching]

Skip AMD, low load power draw is very high (anything from browsing the web, idle, working on excel spreadsheets etc.).

 

[PixelButts]

What do you want it to be efficient in? Games? Rendering? Other type of work? Or at idle / light browsing / media playback? There are too many criteria to choose with.

My workloads change radically very often. Sometimes I have to deal with code compile, sometimes I have to deal with rendering, and sometimes I have to deal with really unstable tools that like to eat my RAM, as well as an occasional application that pings stuff and runs a chain of cpu-intensive processes every 30 minutes.
For example, I have

• A machine dedicated to AI processing, a threadripper + a large capacity of vram
• A mini pc handling archival related stuff with a large amount of attached storage, this one is easily the worst due to physical issues with dealing with it
• A normal desktop for normal gaming and multimedia affairs, including rendering
• A work laptop with a really awful config because of the above (I have been able to justify dual lan ports on one for my work, it's bad)

I'm looking for a jack of all trades kind of config I suppose, but ideally I wanted to know what others would consider for this kind of thing as well even if it's not an all-rounder.

 

[lambda]

Well, my build is largely cost and space efficient assuming you can call this a build.

Here are the parts, not in any particular order:
1. CPU - i5 8400 (turbo can be disabled in the BIOS)
2. 32GB DDR4 3200mhz
3. Quadro P1000 (50W total power budget)
4. 2x WD SN 570 512GB (just cause I had them laying around)
5. Lenovo P330 Tiny chassis + motherboard (the "build")
6. 175w external laptop style PSU.

All of the parts are from second hand shops.

It's decent although not performant enough for anything remotely intensive.

Can run games if you turn the settings down low enough. I've been unable to find a reasonably priced single slot half height GPU to upgrade this mini PC.

I run Ubuntu on it since I got tired of the constant updates and advertisements in Windows.

This isn't power efficient (if take the perfomance into account) but since new stuff costs so much I'm mostly happy with it.

 

[lambda]

Minisforum has these ITX boards with soldered on mobile CPUs from both Intel and AMD.

These can be a good starting point for small SFF style builds but YMMV.

 

[Wirko]

My workloads change radically very often.

Hm. I've never thought about that before, but maybe there exists an app that tracks and shows you some long-term CPU stats, such as average load %, time spent on idle, and time spent close to 100%. So you'd know what matters more when looking for a CPU.

Skip AMD, low load power draw is very high

Indeed it is, unless monolithic chips are also an option.

 

[AusWolf]

My workloads change radically very often. Sometimes I have to deal with code compile, sometimes I have to deal with rendering, and sometimes I have to deal with really unstable tools that like to eat my RAM, as well as an occasional application that pings stuff and runs a chain of cpu-intensive processes every 30 minutes.
For example, I have

• A machine dedicated to AI processing, a threadripper + a large capacity of vram
• A mini pc handling archival related stuff with a large amount of attached storage, this one is easily the worst due to physical issues with dealing with it
• A normal desktop for normal gaming and multimedia affairs, including rendering
• A work laptop with a really awful config because of the above (I have been able to justify dual lan ports on one for my work, it's bad)

I'm looking for a jack of all trades kind of config I suppose, but ideally I wanted to know what others would consider for this kind of thing as well even if it's not an all-rounder.

In that case, maybe someone else who knows more about that stuff can help you more. Here's a few of my general recommendations:

• For gaming, there is nothing as efficient as the 7800X3D. The 9800X3D is faster, but it consumes way more power.
• For idle, or light load, you'd want an Intel, or non-chiplet AMD setup, such as an 8700G.
• For heavy work, a Ryzen 9 or Core i9 would be great, depending on your needs (check reviews).
• As for GPUs, check reviews and see which one suits your needs best.

 

[PixelButts]

Skip AMD, low load power draw is very high (anything from browsing the web, idle, working on excel spreadsheets etc.).

I'm not overly worried about idle/low load power draw in this scenario, rather the high wattage under load/doing stuff is what I'm worried about as I'd like to lower it across the board in more sensible ways. I suppose I should edit the OP to clarify this.

Minisforum has these ITX boards with soldered on mobile CPUs from both Intel and AMD.

These can be a good starting point for small SFF style builds but YMMV.

Downsizing a threadripper 5000 and a 7900 XTX isnt really fun, but if it means I can drop my power bill by a couple bucks on average for doing the same amount with it, it might be worth it. SFF has been where I've been steering myself as it is. The Framework desktop caught my eye as a solution, but only to a point. There's no metrics out yet for how good it actually is, and its clearly geared to text models which okay sure, but lack of 16x PCI-E slot means im only gonna have that onboard 8060S available so how much will that hurt GPU-dependent tasks I do (a lot). It stopped making sense for its pricepoint, and that I'd probably be opting for 2 of them anyway one at the max spec and another at the base spec. It's on my list to look at later once more info comes out.

In that case, maybe someone else who knows more about that stuff can help you more. Here's a few of my general recommendations:

• For gaming, there is nothing as efficient as the 7800X3D. The 9800X3D is faster, but it consumes way more power.
• For idle, or light load, you'd want an Intel, or non-chiplet AMD setup, such as an 8700G.
• For heavy work, a Ryzen 9 or Core i9 would be great, depending on your needs (check reviews).
• As for GPUs, check reviews and see which one suits your needs best.

I didn't consider the monolithic vs chiplet design being a factor. Heavy work is hard to say since again my needs radically change a lot so it's kinda hard to say if I'd truly *need* one in that range. The things my threadripper does can be accomplished with a basic AM5 CPU right now for a fraction of the power draw, but boy howdy is that code compile nuts when I need it.
Gaming wise, while I am agreeing that the 7800X3D is great, the 7600X3D is also genuinely impressive given its 65W TDP given the benchmarks Gamers Nexus put up. It's an uncommon CPU choice but it's certainly no slouch either especially since I already have one and it feels weird seeing it outperform my 7950X in a number of tasks.
Board wise I have some ideas in mind too, since I've been going over a series of them and their manuals to see which is ideal for my scenarios and I settled on a handful if I go the ITX board route. The fact there's a board out there that has no lane sharing, lets me drive PCI-E 5.0 on GPU and M.2, and still have a gen 4 on another M.2 and have no bottleneck if all are populated is nuts to me.

I appreciate the replies so far everyone, sorry for this being a somewhat unclear intent though. Again my situation is a bit of a mess and that's part of the reason to look into my options here. I definitely recognize I'd have to give up something somewhere to accomplish this.

 

[agent_x007]

Since you want efficiency, performance will not be matched to stock settings (unless you aren't as efficiency oriented as you claim to be ). That's due to ALL manufacturers pushing cards past V/F "sweetspots" (all for the sake of performance).
Some time ago, I did a max. undervolt test with few older cards : LINK, but summary is this :
Newest gen GPUs will boost to high watts regardless of undervolting, due to transistor density and architecture efficiency (with power limit simply being hit less often vs. stock due to reduced voltages).
If you want a energy efficient GPU for undervolting, don't go over 4070 (Ti) die size.
I didn't tested RDNA3(4), so can't give my recommendation with those.
Lastly : Personally, I prefer to have maximum adjustability possible, and because of that 7000X3D series isn't for me.

 

[PixelButts]

Since you want efficiency, performance will not be matched to stock settings (unless you aren't as efficiency oriented as you claim to be ). That's due to ALL manufacturers pushing cards past V/F "sweetspots" (all for the sake of performance).
Some time ago, I did a max. undervolt test with few older cards : LINK, but summary is this :
Newest gen GPUs will boost to high watts regardless of undervolting, due to transistor density and architecture efficiency (with power limit simply being hit less often vs. stock due to reduced voltages).
If you want a energy efficient GPU for undervolting, don't go over 4070 (Ti) die size.
I didn't tested RDNA3(4), so can't give my recommendation with those.

This is actually very helpful, thanks for that link. As for my preferences, I prefer not to care about my electricity consumption, but lately I have been losing that luxury so any way to lower my power draw without giving up TOO much performance it is a good answer. For example I could just throw in this A2000 I have and call it a day but the performance loss in doing that is too much to satisfy my work needs now.

 

[Macro Device]

Since you yourself have no idea what exactly will be going on on your machine lemme clear some things out:

• Generally, within one CPU architecture, more cores at lower clocks is better for peak load scenarios. So, say, instead of 7600X3D you can pick 7800X3D, clock it 300odd MHz lower and get even lesser power draw, also destroying this 6-core chip in applications where there's no such thing as enough cores. If you go gaming or anything else where single thread speed matters you could just let it go wild via allowing higher clocks in such scenarios (probably will cost you having additional BIOS profiles).
• GPUs work in a similar manner but additional VRAM chips really do hurt efficiency so 5080 is preferrable to 4090, unless you're VRAM starved and 16 GB won't get you anywhere. Generally you get the fastest GPU you can afford that doesn't have too many VRAM modules and you heavily undervolt the die, also allowing VRAM to run at its full potential. For some especially GPU-happy workloads that're light in VRAM bandwidth requirements and for 1080p±RT/1440p non-RT gaming, this is basically nonsensical, you should leave VRAM at stock for these cases.
• RAM: you're basically limited by silicon lottery and your wallet but you'd wanna ideally only use two RAM sticks clocked relatively low, with timings tightened to the point you mitigated most of it without going ham on additional voltage. Higher RAM clocks ask for more IMC clocks to be efficient and it's about to get really messy really fast. Unless you truly need ridiculously much of obscenely fast RAM, pick a kit of two highest density modules and tune it to be as fast as it can without drawing additional power. 5600CL30 seems reasonable. Sure, it's slower than the performance sweet spot of 6000C28 by a significant margin but it'll be way more power efficient.
• Storage: go higher density and lower amounts. Avoid PCI-e 5.0 and other speed demon kinds of drives. Avoid HDDs, unless you can't get enough storage space with SSDs.
• Motherboard: go as simple as possible. A620 / H610 motherboards draw way less power than their X670 / Z790 counterparts simply because they have way less going on on them. Of course you might need some connectivity or any other thing unavailable on the lowest end chipsets so go figure.
• Fans: I heard Arctic and Noctua do make mighty efficient fans but I'm not sure if the source was right. Generally you want more millimeters and less RPM.
• PSU: probably one of the most important parts. Get a PSU with as super of efficiency as you can. Since you're about to undervolt and downclock everything anyway it's gonna be a low wattage build so you want a PSU that's stupid efficient at this low point. 1+ kW PSUs do that job generally fine but they're designed to be efficient at 500 W and higher and it's not gonna happen with your build. Maybe some S-tier 600 W PSU..? Not sure.

 

[Epaminombas]

What a pointless and pointless topic.

If you want to spend less energy in a game, just limit the FPS to 60/80/100.

There is no such thing as spending less energy in AI, image, video processing.

But in terms of conventional desktop hardware.

AMD 9800X3D uses less energy.

And i7 14700 without K and i9 14900 without K use less energy.

i7 265 without K uses less.

i9 285 without K uses less.

Intel CPUs without K use 40% less energy.

 

[PixelButts]

Since you yourself have no idea what exactly will be going on on your machine

Definitely not a fun problem to have isn't it? Much appreciated regardless.

What a pointless and pointless topic.

I dont think so, but I definitely didn't open this thread right. I tend to be incredibly wasteful, so any advice is worthwhile to me right now in my situation. For example I've already decided to lower the clocks on what I already have in-use just to lower it a little further, but it's more ideal to just replace 2 of these machines with new configurations. I've already gotten some good enough replies to know what to aim for now.

If this thread is truly pointless a mod can close it now if desired.

 

[TumbleGeorge]

For workload maybe must choose RTX 4000 SFF Ada generation. Have same 70 watts power consumption like RTX A2000 but with better performance and 20GB VRAM vs 12GB. If performance is not enough next choice is normal RTX 4000 Ada generation with 130 watts TDP.

 

[Macro Device]

Definitely not a fun problem to have isn't it?

It's my pleasure to twist my braincells on my extended lunch break since I've typed 2 million worth of characters this half-month whilst writing the story, quests, characters and whatnot for my video game. Relaxed to type something else.

 

[Count von Schwalbe]

Locked per OP request.