Build a PC

665 readers

7 users here now

Planning on building a computer but need some advice? This is the place to ask!

Planning on building a computer but need some advice? This is the place to ask! /c/buildapc is a community-driven place dedicated to custom PC assembly. Anyone is welcome to seek the input of our helpful community as they piece together their desktop.

founded 2 years ago

MODERATORS

[email protected]

Will I need a new PSU for a GPU upgrade? (beehaw.org)

submitted 8 months ago* (last edited 8 months ago) by [email protected] to c/[email protected]

7 comments fedilink hide all child comments

So currently I’m running a 5800x and a regular 2060. I’ve got a 650w gold PSU that’s about 4 years old, no problems with it at all. I’m thinking about upgrading to a RX 7800 XT because GeForce prices are perpetually absurd. It seems like it would be enough power, but the few things I’ve read say that I need at least a 750w if I go with the AMD (because they’re power hungry?), but 650w would be fine for a 4070ti. If I have to buy a new PSU, I feel like it would wipe out any savings I might get by buying AMD over Nvidia. How can I definitively know if I need more power?

Full disclosure, I understand the concept of undervolting, but I’m not nearly confident enough to mess with the settings.

all 11 comments

sorted by: hot top controversial new old

[–] [email protected] 4 points 8 months ago (1 children)

What AiB are you getting? A board partner like Gigabyte or Asus have factory overclocked cards that are more power hungry than a reference 7800xt. And AMD already states 700w as a minimum recommendation. Nvidia also states 700w for the 4070ti. Same thing happens, board partner cards will draw more power.

I’d stick with 750w at minimum. Give yourself more overhead since psu’s are more efficient that way.

Either way, the current cards are power hungry. There’s no way around it without going for a lower tier card, but at that point I don’t think the gains are worth it. Maybe a regular 3070 if you can find one cheap enough.

[–] [email protected] 2 points 8 months ago

I was looking at MSI or Asus, but I’m not married to a brand.

I’ll just suck it up and buy a new PSU, and use the old parts for something else. The money isn’t a problem, so it would be dumb to melt something after spending that much on a gpu. Just considering trying to save a buck, but it sounds like it’s not worth it. Thanks for the advice!

[–] [email protected] 3 points 8 months ago* (last edited 8 months ago)

The 7800XT (263W) has over 100W higher TDP than the 2060 (160W). It ultimately comes down to what other components you have, but you will be pushing the ceiling on a 650W PSU with the 5800X (105W).

You are under the limit based on TDP, but during peak loads, may not have enough overhead to not reduce the life of your components. That said, if you have fewer than 4 DIMMs of RAM, and only M.2 SSD storage, you are probably fine.

Let’s round up and say 75W for Mobo, 32W for RAM, 10W for storage, and 5W for LEDs, you come out right at 500W. Add 20% for thermal overhead, and you’ve got 600W. Very close, but should barely be stable.

This assumes a reference GPU. An OC edition could easily blow this calculation, but do your own math.

Definitively, buy a kill-o-watt, fire up a CPU+GPU stress test, and measure power draw at the wall. Add 100-200W to account for the new card, and see if it exceeds 650W.

[–] [email protected] 2 points 8 months ago (1 children)

Pcpartpicker.com

Put your build in then change the components to the new ones

[–] [email protected] 1 points 7 months ago* (last edited 7 months ago)

Thanks for that, that’s helpful!

Old: https://pcpartpicker.com/list/dpLb6D -426w New: https://pcpartpicker.com/list/JYByBL - 526w

If I add a 20% buffer and count all the fans, I’m really close to 650. Also thinking about adding another SATA SSD also.

[–] Still 1 points 8 months ago

like you'll be fine, but id get and 850 so you stay at the peak efficiency marks

[–] [email protected] 1 points 8 months ago* (last edited 7 months ago)

I'm running a 3080 and a 5600x on a 650w psu (the only one I could find in my budget in sfx form factor). It's been fine, but I kinda feel like it's already pushing it. Because of the 5800x I'd suggest go 750w.