CPU power consumption

[darael]

In my spec me thread, in GH, I've been doing some poking around with TDP and power consumption figures.

Basically my goal is replace my E8400 (E0) with something more power efficient, particularly when idle. But when I've been trying to find idle figures, I've found it's quite hard to actually find them and I end up using TDP figures, which I imagine is the CPU's maximum power draw?

The CPU won't do too much work, maybe the odd bit of encoding, some light gaming now and then and web browsing. For this reason I'm half tempted to go for an i3, but I've been given to understand these are more or less like old Celerons...gutless.

The idle power consumption is especially important as the computer is always on. I've had a scare or two with harddrives nearly failing when powering my machine up, hence I'd prefer to keep the drives spinning constantly. This will change when 2TB SSDs are affordable, but in the meantime I will put up with the downsides of harddrives.

So, does anybody have any information or advice for me? The last thing I want to do is upgrade and see my electric bills bounce up! I could live with the same power draw as my E8400, but if upgrading means I'm going to regret it, then I'd rather keep my E8400 for now until processors become more efficient.

 

[wazza300]

tdp means thermal design point

it means the typical temp the cpu can generate

i think an i5 and i7 would use the same or less power than your older e8400 due to all the new power saving

 

[darael]

I'm in two minds just getting a lower clock i5 instead of the 3.5GHz 4690k that I'm being recommended. Any i5 is going to be an upgrade to my E8400 and I'm not altogether sure I can justify 3.5GHz other than for the hell of it. I'm leaning towards the 4440 as it's cheaper than the 4430 and they bother have a lower TDP - which, as I understand it, means less power.

Am I right in reading that these i5's can be quite warm?

 

[wazza300]

no it means less thermal heat produced

tdp thermal design point

i hardly notice my 2600k at 4.5ghz,it uses 7watt idle in aida64 and around 80w on full 100% cpu stress test in intel burn test

idle

how accurate it is idk (cpu package)

 

[RobCrezz]

Modern i3s are very good actually - around 40-70% faster than your E8400 depending on work load. All while consuming 10w less tdp, and quite a bit less on idle and light loads due to the new power saving features.

 

[Raiden85]

Idle power consumption on Haswell is very good. Watching HD Freeview on Windows media center on Windows 8.1, my 4790k at stock is only drawing an average of 3w.

My previous 3770k also at stock would draw around 10w doing the same thing.

 

[mrham4321]

One of the higher-end i3s will be very energy efficient for the power, which will be also be a notable increase over your old E8400.

 

[Sasahara]

Idle power consumption won't be much difference and certainly not much lower as there isn't much to drop.

http://www.nordichardware.com/CPU-Chipset/intel-core-2-duo-e0-vs-c0/Power-consumption.html

As you can see at 4.3W any replacement can't be significantly better and may be worse, but most likely very similar for a 2 core or 2/2 Hyperthread CPU

Chipset and graphics in particular are going to be the biggest impact on idle power consumption.

In the days of the E8400 it was the graphics cards that had high idle power consumption.

So really you just need to decide if you need a faster CPU.

 

[joeyjojo]

If you're concerned about idle power consumption (and you shouldn't be as you're splitting hairs, you're looking at saving about 1 p off your electricity bill per year for every W you shave off!) then you're number one priority should be the PSU. Reason being, if your machine is idling at say 30 W, and you have a 300 W PSU, that's only 10% load. At this kind of very low load the PSU is going to be very inefficient, probably less than 80%, so something like 6+ W will be wasted in the PSU, which is quite a big percentage of the total. You really want a very efficient 100 W or so PSU for a low power machine like an i3.

Then you mention gaming, which is the opposite end of the spectrum, unless you're planning to use a very low power GPU like the 750 Ti. What kind of gaming experience are you expecting?