Will I need a bigger PSU?

[Bigian88]

Im buying:
A HD 5770 off Massimo to replace my 9800GT
A NZXT fan controller off VJ
4GB 1600Mhz DDR3 off Nick42, replacing my current RAM.

I realise this will be sucking up a bit more power than my current setup and im wondering will my 400w OCZ supply enough power to run it all? Or should i spend a bit more money on a 600W version?

[AaronWHUFC]

400W is fine. What CPU/Overclock?

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[callumburns]

i think it should be ok but perhaps pushing it a little

[El Wayneo]

It'll be fine mate.

Youll run about 300W.

[Bigian88]

i know little about power consumption from components so id rather be safe and ask than plug it all in for it to sizzle and die :o

[jbromley]

From those comps you'll be okay, what drives are you running though?

[El Wayneo]

Andrew Moore ran a HD5770 and a massively OC'ed i3 530 so i think it'll be okay.

[NickCPC]

My rig is similar to yours, except I've overclocked the nuts off my CPU and unlocked it to a quad, with a more power-hungry GPU, and my 400W unit is fine :thumb:

[sunjoo]

yeah your psu should handle it fine

[Bigian88]

My rig is similar to yours, except I've overclocked the nuts off my CPU and unlocked it to a quad, with a more power-hungry GPU, and my 400W unit is fine :thumb:


my CPU was a tri-core 435 and ive unlocked the 4th core and overclocked it by 600Mhz

[NickCPC]

my CPU was a tri-core 435 and ive unlocked the 4th core and overclocked it by 600Mhz

Ah right, I just read your sig, sorry. It should be fine though :)

[Bigian88]

sweet :)

[AmdOverclocker]

sweet :)


yeah, a 5770 will never consume more than 100w, (maybe 125w max) so, 100w, + 125w for the cpu (guess since you unlocked to quad), + lest say, i dunno, 150w for mobo, HDD, DVD etc, so thats 100w + 150w + 125w = about 375w, but thats just a rough guess, and btw i over specced alot, so as el wayneo said you wont consume more than 300w ish, 350w at the most.

when you want to upgrade to a second, thats when youve got to get a 500w+ one, btw nvidia and ati over spec thier GPU's PSU requirements ALOT, just for headroom.

[NickCPC]

yeah, a 5770 will never consume more than 100w, (maybe 125w max) so, 100w, + 125w for the cpu (guess since you unlocked to quad), + lest say, i dunno, 150w for mobo, HDD, DVD etc, so thats 100w + 150w + 125w = about 375w, but thats just a rough guess, and btw i over specced alot, so as el wayneo said you wont consume more than 300w ish, 350w at the most.

when you want to upgrade to a second, thats when youve got to get a 500w+ one, btw nvidia and ati over spec thier GPU's PSU requirements ALOT, just for headroom.
O_o Where did you get that from?! Most motherboards, even if they have all their USB ports filled, and you've overclocked the chipset, will pull no more than 40W. An HDD is 3-4W, maybe 10W on startup, fans throughout the case even less. If anything, the CPU and GPU is likely to take more than you estimated, especially if overclocked. I'd be surprised if at 100% torture load on both GPU and CPU simultaneously, he'd get over 300W. My rig on a GPU blend test (100% load) and CPU at 3.8GHz on Prime95 (again 100% load) with fans on fastest pulled 280W max.

Also nVidia and AMD/ATI specify those wattages because some of their customers actually have their GPUs at 100% load for extended periods of time, for instance when folding. They are generally accurate representations of what such users need and, if anything, are a little conservative especially considering the average users buy generic piles of crap for PSUs. Can you imagine how annoyed you'd be if you were doing F@H and were told a 600W PSU is what you need for a couple of high end graphics cards, only to find that you actually need 650W and consequently your PC wouldn't boot? I know I'd be livid.

[Bigian88]

just did a bit of research and punched some figures:

CPU under load - 159w
2x Hard drives under load - 13.6w (6.8w each)
Memory - 40w (approx 20w each)
Gfx under load - 108W
5x case fans - 18w (approx 4w each)

leaves me with about 32w spare which i assume my motherboard will use a bit of (couldnt find a figure for power concumption)