Possible upgrade - PSU sufficient?

David Bisset · 4 Jul 2013 at 16:20

Hi all,

I've got an old desktop that I'm considering refreshing with a new graphics card. Not looking to make it actually decent or anything, just better. However, a power surge pried my old PSU a while back and when I replaced it I was feeling like I wouldn't upgrade so was pretty conservative. I'm wondering if I can make improvements without replacing the PSU too.

Pre-upgrade:
CPU: i5 750 @ 3.2 (Can go much higher but this is my 'normal', stock volts clocks) w. Arctic Freezer 7 rev 2
Mobo: Asus p7p55d-le
Ram: 4GB Corsair 1600MHz C8 (2*2GB)
GPU: Sapphire HD 5750 w. Arctic Acelero Mono Plus VGA cooler
PSU: Corsair Builder Series CX 430W V2 '80 Plus Bronze' Power Supply
HDD: Single spinny-platter of some variety
Other bits: TV card of some type, DVD drive

What I am thinking of getting:
HIS 7850
A quick glance suggests this is a 46W increase in max draw but I've no idea what I'm drawing now so not sure if I can do this or not. It is probably a smaller increase as my current graphics card is overclocked (can't remember off the top of my head how much, I'd need to check and am at work just now) but then one of the advantages of the linked card is apparently its overclockability.

Would this work? Be feasible? Give a noticable improvement?

etc etc.

pastymuncher · 4 Jul 2013 at 17:10

Should be ok. The CX430v2 only has 336w on the 12v rail so clock the nuts off the cpu and card and you will be pushing it to it's limit.

Yes it will be a nice upgrade graphics wise. Quite a big one actually.

David Bisset · 4 Jul 2013 at 20:49

Cool, a little close to the boundaries of the PSU. Is there an easy way of telling how much I'm actually drawing on a rail &/or total? I could afford to upgrade the PSU if necessary.

Possible upgrade options (feel free to suggest others!):
Corsair 500W CX V2
Seasonic S12II 520W

Edit: If I can check what I'm actually drawing I'll happily take your advice and stick with what I've got, just it'd be nice to be able to overclock without worrying so if I can't check how close to the limits I am then maybe I'll go the upgrade route...

olivier renault · 5 Jul 2013 at 08:57

use one of those Kill-A-Watt plug monitors if you want. It's like £15 so when thinking of buying a £50 PSU, that's a fair chunk added on top

But it will tell you the power draw at the other end of the PSU, so you have to factor in the loss of efficiency as well (record 300W at the plug, 80% estimated efficiency, components draw 240W). But if you run into those margins, your PSU is already well stressed.

Here's a datasheet and reviews of most common power supplies.

http://www.realhardtechx.com/index_archivos/Page541.htm

The CX500 / CX500M have 38A on 12V. That's more than enough for a 7850. I suspect you will be drawing around 300W. Also consider a NVidia GTX 660. It's a bit quicker at stock, if you are not into that overclocking.

I would prefer the Seasonic S12II, personally. Seasonic makes good stuff.

YOu also have the XFX Core 550W that should be around your budget. Good gaming PSU.

pastymuncher · 5 Jul 2013 at 09:04

Easiest way to see how much you are pulling would best to buy a plug in power meter. The energenie one on ocuk is out of stock at the moment but you should best able to get one from the likes of B&Q for £12-15. If you find you are close to the limit don't get another CX series. I really don't rate them. They are underpowered and built down to a budget using cheap caps. Stick with the- likes of seasonic, xfx (built by seasonic), enermax or the better corsair units.

David Bisset · 5 Jul 2013 at 10:57

Thanks guys, I'll probably get the seasonic then. £15ish for a monitor isn't much but as you say its a bit of a waste given the PSU isn't that much more anyway. That, and I know someone that'll take my old PSU off me, so cutting the cost further

The reason for the 7850 over the GTX 660 is the deal on at the moment with a whole bunch of games with the 7850 makes it seem better value to me. My laptop already has a GTX 660M so a different number on the desktop seems more exciting anyway

olivier renault · 5 Jul 2013 at 11:16

David Bisset said:
Thanks guys, I'll probably get the seasonic then. £15ish for a monitor isn't much but as you say its a bit of a waste given the PSU isn't that much more anyway. That, and I know someone that'll take my old PSU off me, so cutting the cost further

The reason for the 7850 over the GTX 660 is the deal on at the moment with a whole bunch of games with the 7850 makes it seem better value to me. My laptop already has a GTX 660M so a different number on the desktop seems more exciting anyway

Cool. The 7850 is a good card, and overclocks well. For the same money, it's a tough choice since a GTX 660 is in between a 7850 and a 7870. But free games... Up to you.

David Bisset · 5 Jul 2013 at 16:26

Gone for it and ordered the 520 Seasonic and the 7850. I fully intend to clock it quite a bit so hopefully that'll help make up some ground on the GTX 660. The desire to clock being the main reason I felt I needed to replace the PSU!

Thanks olivier and pasty, much appreciated!