Power efficient build

Re Core i5 4570S being more power efficient over regular i5 4570 I don't think it is, I'll explain.

So you have the situation where the CPU is fully loaded, say using WinRar or encoding a video. So the core speed will be increased to maximum of either of the CPU's.

Now the S version CPU will use less power to operate at this point, however because the S has less computational power the S will take longer to complete the task over regular i5. So the regular i5 will return to idle faster as it will complete the task faster than S version.

So the power saving you gain from the S is lost, as the S has to hold it's full core speed longer than the regular i5 to execute the same instructions.

When you look at the above, the only benefit of S is reduced peak thermal output.
 
^ I wrote the same thing in #32. 90% of the TDP difference is explained by the clock speed. The other 10% must (presumably) come from the reduced voltage.

Another way to look at it is "clock speed-per-watt". The -S is 2.9/65 = 0.045, the normal is 3.5/88 = 0.040. So the -S comes out about 12% more energy efficient.
 
joeyjojo said:
Another way to look at it is "clock speed-per-watt". The -S is 2.9/65 = 0.045, the normal is 3.5/88 = 0.040. So the -S comes out about 12% more energy efficient.
Click to expand...
Clock speed does not equal actual speed.


Its the age old argument of "quicker running at higher power" vs "slower running at low power".
Theres arguments for it either way and its not a black & white subject and is highly subjective based on workload.
The difference in real word performance between an i3 and the top i7 for most tasks that computers are used for is less than 10% anyway. So the difference lies in those few tasks that work the processor. In the case of what i'm doing with it, gaming, the difference in fps in most common titles is again, less than 10% difference for more than a 10% price increase and a guaranteed power increase.
 
Your argument that the CPU won't be highly loaded most of the time makes getting the -S CPU even worse. It's only at high loads you'll notice any power savings! :p

I understand that low-power is a priority so getting the -S CPU makes sense as you're more likely to get a low VID chip. But for a best case scenario of 20 W saving it's really not worth it IMO. If you're certain you'll never want to overclock, the 4590 is faster and cheaper. If there's a chance of overclocking in the future the K is a bit more expensive but will give you a free 25%+ boost should you need it.

I won't bother you again with this point, enjoy whichever CPU you go for. :)
 
joeyjojo said:
Your argument that...
Click to expand...
Im not arguing either way, i'm just pointing out theres two trains of thought to the subject. Devil advocate to my own question if you will. :p

I won't bother you again with this point, enjoy whichever CPU you go for. :)
Click to expand...
I don't mind the discussion tbh, im not arrogant to think i know more, so other views are welcome. :)

Re: 4590
Few quid cheaper, 19w more power...
I suppose if i'm buying a big HSF then the extra 19w is moot potentially, i'd need to research more though.
 
I know i maybe repeating myself here, but this is how you build efficient builds.

You buy the latest generation most power efficient CPU technology, so currently that's any of the desktop Haswells.

You choose a main board with the least features, as in reviews these are always more efficient.

If possible use the integrated GPU, otherwise get latest generation graphics card, your looking for something with low idle. Go into graphics card setting and ensure your on adaptive and power saving mode.

Then use an SSD as main drive as these idle at around 0.5 w compared to a 7.2k HDD that idles at around 7w. Other media drives are less important as these will standby but your boot drive will never standby when the computers in use.

Choose a PSU that's very efficient (90%+), also important it's efficient in the power range you normally use so around the 100-150w mark.

Make sure the PSU is really stable, because the more stable the more you can undervolt!

Set your fan profiles to only operate fans at required speed, if you have a case that assists cooling that is a bonus.
 
Last edited:
BoomAM said:
Does anyone have any opinion on the Gigabyte Z97 board?
https://www.overclockers.co.uk/showproduct.php?prodid=MB-504-GI

Same price as the MSI i was planning on, but with better PCI-E support it seems...thoughts?
Click to expand...

I have used around 3 now in various builds.

Its good, the overclocking is ok (but no use to you and he CPU you want) and it has plenty of connectivity.

Did you need SLI support?

This one is ok with a single GFX card - https://www.overclockers.co.uk/showproduct.php?prodid=MB-498-GI&groupid=701&catid=5&subcat=2811

Make sure they have the latest BIOS on them.
 
Hate to say it but you can get that board+4690K as a bundle that saves money than buying separately.
 
stulid said:
Hate to say it but you can get that board+4690K as a bundle that saves money than buying separately.
Click to expand...

Thats actually very tempting, dont understand how a processor that is £40 more works out £12 cheaper in a bundle though.:p
Devils Canyon is the successor to Haswell, correct?
 
Its not cheaper than the 4570S+board, as the CPU is much cheaper than a 4690K.

Devils canyon is the Haswell refresh.

A 4670K and 4690K both use the Haswell architecture, the 4690K just runs faster and has a few tweaks to reduce temps.

If a 4670K and 4690K are both running at 4Ghz, they both give the same performance.
 
Ordered! :)

- Intel Core i5-4570S
- NZXT H440 Mid Tower Case
- Gigabyte Z97X-SLI Intel Z97
- TeamGroup Elite Black 16GB (2x8GB) DDR3 PC3-12800C11 1600MHz

Fingers crossed that my heatsink works. :)
 
Im thinking of just buying a HSF regardless.
Problem is that a few reviews shows the mobos RAM slots to be nearer the CPU than normal by 2-3mm, not really an issue, but for big HSFs it could be.

Any suggestions?
The Raijintik DirectContact one looks the best, fit wise...
 
You have ordered low profile RAM, so take your pick of coolers.

The Themis at £20 fits that case.
 
stulid said:
You have ordered low profile RAM, so take your pick of coolers.

The Themis at £20 fits that case.
Click to expand...

Ended up going for the BeQuiet! Pure Rock + MX2 Heat Compound.

Seems ok up to now.
I'm fairly certain that the majority of the noise i'm hearing at the moment is coming from the aging HSF on the 6870 card. But its certainly no louder than my last system, maybe even slightly quieter. Its noticeably quicker though. SSD test shows that alone has seen a doubling in performance on both MB/s and IOPs purely from going from a 3Gbps SATA connector to 6Gbps connector.

Once the compound has "set" i'd expect temperatures to get a little better, but at the moment the CPUs hovering between 38-41*c. All its doing is installing programs and updates thus far.
That's with the mobo set to have all the case fans at "silent" and the CPU to be adjustable based on temperature.

Its also amusing that what the enthusiast community considers "low profile" RAM isnt technically low profile RAM.
So when ive been sat in the OCUK carpark waiting for it to open this morning, reading reviews on HSFs on my phone, was a bit strange hearing "low profile RAM" on almost every review. More accurate would be "RAM with big HSF". :p

Next decisions will be whether to:
A) Stick it out with the video card & replace when DX4 hits, or upgrade in the next month or two.
B) Get a second SSD to replace my HDD.
:p

##EDIT##
Just took the side off to test, almost all the noise is coming from either the HDD (1x 2Tb WD Green) or the graphics card fan.

##EDIT 2##
Idling doing nothing it drops to about 30-33*c across the cores.
Playing Portal for 30mins, dism doing a component cleanup in the background and a three way Skype video call on another monitor, it averaged 41-43*c -- more than acceptable. :)

##EDIT 3##
IntelBurnTest 10x run @ Max.
Fully stable, highest temp i saw was 59*c on the processor intermittently, mostly stayed below 56*c. That's with all the fans at 25%...pleased with that! :)
 
Last edited:
You must log in or register to reply here.
Back
Top Bottom