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Is TDP important? Bills?

aiden_r

aiden_r

aiden_r

Associate
Joined
11 Nov 2013
Posts
20
Hi!

I just had a quick question about CPUs. I noticed Intel CPUs seem to be a lot more power efficient. Ie. the best AMD CPU has a TDP of 125W and the best Haswell CPU has a TDP of 84W. Does this actually have a big impact on electricity bills? If so I might take more notice next time I make a PC!

Thank you :)
 
It's not massive:

comparing stock i7 4770K (84W) vs a FX 8350 (125W) there is a 41W difference (at full load). If you run your PC for 8 hours per day, then that's 0.328kWh of electricity per day (or 4.6p per day at 14p per kWh).

Over a year that translates to around £17 difference.

However, both CPUs are unlikley to be running at 100% load for 8 hours per day and they have very efficient low-power modes - so the price difference is likely to be a fair bit less.

Intel's power efficiency advantage is mainly aimed at the laptop and tablet markets where power efficient CPUs are much more important.
 
cmndr_andi said:
It's not massive:

comparing stock i7 4770K (84W) vs a FX 8350 (125W) there is a 41W difference (at full load). If you run your PC for 8 hours per day, then that's 0.328kWh of electricity per day (or 4.6p per day at 14p per kWh).

Over a year that translates to around £17 difference.
Click to expand...

Don't forget that Intel's TDP figure includes the onboard GPU, if you aren't using the onboard GPU the TDP of an Intel processor will be considerably lower.

The electricity bill doesn't bother me personally, my biggest problem with FX8350 was the heat output and struggling to keep it under AMD spec when overclocked and put under stress.
 
Interesting, thanks! When people talk about electricity bills maybe they are normally talking about graphics cards instead, I just thought I'd seen people mention it a few times, but 17 quid a year is nothing!

Cheers :)
 
My whole system below when idling, browsing, office etc. is at 130W. The most I have seen at the wall is 270W when priming 8 cores at 4.6GHz and 370W when priming and heaven 2.5 bench concurrently.

Only a single 7870 not overclocked but a rreasonably efficient system load.
 
Am guilty as charged I have been posting here and there with the questions on electricity lately.

But like cmndr_andi said very well were talking low cost in electricity.

I checked my gas bills online and worked out roughly am using 30-40 quid of electricity per month that is with a core i5 quad basic tower pc (non gaming) on most of the day.

In comparison you could get an intel nuc which consumes even less electricity around 15watts for general usage (more for surfing/movies) and that would use about 50p per week even if switched on 24/7.

Gives a rough idea I hope.

Its the gaming side of things that got me a bit concerned especially with those monster power n hot consuming gpus lately ! But I take it am worried for nothing but not 100% on that yet!
 
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Actually does anyone know how much electricity a top end Core i7 or AMD system with 780/290 electricity cost roughly per month ?

(someone who games for few hours ie BF4)
 
It will depend a lot on how you use the PC, but here is my attempt:

Playing games it's reasonable to assume that a 250W GPU and a 85W CPU with a decent overclock and the other parts will be drawing around 450W.

Also, the PSU is not 100% efficient (which I didn't take into account with the earlier case), so add on an extra ~10% to get the power drawn from the wall - so 500W.

If you assume it is doing high-power stuff (500W) for 5 hours per day and low power stuff (200W) for 5 hours, using 2.5kWh and 1.0kWh respectively (total of 3.5kWh per day).

Assume 30 days in a month for 30 x 3.5 = 105kWh.

Using 14p per kWh a heavily used high-end gaming PC will cost around £15 per month in electricity.
 
thanks cmndr andi that puts it right into perspective guess really am worrying about AMD and intel and gpus taking over the electricity bill when no need to :)
 
On my spec:

[email protected]
8GB DDR3
2x 840 250GB SSD
1x M500 240 SSD
Gigabyte Z87X-OC
Inno3d 780 Herc

With 2x 24" monitors, idling on desktop, browsing internet etc I pull around 100-140watts of electric.

Playing BF4 it jumps to around 450w on initial loading, 390w once in game. Bioshock infinity is even better than that, ticking along 360w-390w in game. At times even lower with me seeing the card lowering its clock when in the same area.

I think most of the numbers reviews show are while running these stupid synthetic tests and in no way reflect real life situations.

My card alone is marked up in most reviews as using more power than my whole machine and monitor on its own. This pretty much highlights how unnecessary pushing our machines through any synthetic tests are and the ridiculous amount of stress it puts on components in a completely non real world scenario.
 
aiden_r said:
Hi!

I just had a quick question about CPUs. I noticed Intel CPUs seem to be a lot more power efficient. Ie. the best AMD CPU has a TDP of 125W and the best Haswell CPU has a TDP of 84W. Does this actually have a big impact on electricity bills? If so I might take more notice next time I make a PC!

Thank you :)
Click to expand...

We dont run at stock on this forum so our TDP's are abit higher ;)
 
When I buy new hardware, new mobo/CPU I do a clean os install and whist installing drivers etc, it's at stock, after that overclocked all the way!!
 
Juggern said:
On my spec:

[email protected]
8GB DDR3
2x 840 250GB SSD
1x M500 240 SSD
Gigabyte Z87X-OC
Inno3d 780 Herc

With 2x 24" monitors, idling on desktop, browsing internet etc I pull around 100-140watts of electric.

Playing BF4 it jumps to around 450w on initial loading, 390w once in game. Bioshock infinity is even better than that, ticking along 360w-390w in game. At times even lower with me seeing the card lowering its clock when in the same area.

I think most of the numbers reviews show are while running these stupid synthetic tests and in no way reflect real life situations.

My card alone is marked up in most reviews as using more power than my whole machine and monitor on its own. This pretty much highlights how unnecessary pushing our machines through any synthetic tests are and the ridiculous amount of stress it puts on components in a completely non real world scenario.
Click to expand...

Can I ask what kind of electricity bills you get roughly per month ?

When overclocked to 4.2 is there not a way to enable speedstep so the cpu can down throttle to like 1ghz making this more energy efficient ?
 
Got a 2600k here at 4.7Ghz at idle (still at 4.7Ghz) its 1.35v (1.38v load) and uses 8w of power according to core temp.
TDP is 95w but hits 105w under full load.

The fans in the case use much more power (at idle) :)
 
I think power difference between Intel and AMD is overblown as an issue.

My system is currently sitting at about 82-84w while at the desktop, couple of browsers with 10-15tabs, couple of VMs, email & IM clients etc.

Asus M5A99X EVO 990X
AMD FX-8350
32GB Crucial Ballistix Sport VLP
Nvidia GTX770
Be Quiet E9 StraightPower 480W
Samsung 256 Evo SSD
WD 2TB Blue
 
When building my main rig I didnt give any thoughts to tdp buy recently when building my nas I decided that even if it wasnt too much of a difference. - I'd rather go for the lower tdp (so long as the price wasnt too extreme) - may add up in the long run.
 
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