PSU required for the job and other factors

[Deleted]

I'm planning to go SLI on my current pc and also to potentially add more RAM as well (from 8 to 16GB), I'm wondering what wattage of PSU to go for or if I could just put in a very large wattage psu and it makes no difference(or the difference is negligible).

Currently my PSU is 650TXM Corsair

PC Specs;

2GB EVGA 670 FTW
8GB DDR3 Vengeance RAM
Intel Core i5 3570
Asus P8Z77-V Mobo
Arctic Cooling Freezer 13 FZ130-BL 92mm
2x 1 TB HDDs both running at 7200rpm
Samsung SH-224BB/BEBE x24 DVDRW
Xonar Audio DG sound card
3 x USB devices (including keyboard & mouse)
There are two other fans although I'm not sure on their size (if it's important for you to know just say and I'll open it up and find out).

Any help on this would be much appreciated.

Second question is, are there any other factors I should take into account when upgrading to SLI? e.g. will I need more cooling?

[chazus]

Wattaged needed: None

A 650w TX is fine for running dual 670s. At peak load (never?) they pull 170w each. Your system will probably not break 400w, ever.

Out of curiousity, what are you doing that needs this power? A 780 costs nearly the same price as another 670, and has almost the same performance. But no sli, much less power used, and just generally better. (You could also sell the 670 as well, so the solution would actually be -much- cheaper)

Also moving this to the build/upgrade subforum

[Str8Tripa]

If cost wise you can avoid crossfire or sli do it!, don't cross that line unless you have lots of screen real estate.

I have a crossfire 3x 7970 in my amd rig and sli 2x 780 in my intel. The performance you will gain will be 20-40% increase in frames but the down sides can be freezing, micro stutter and many more issues. I run it for multi screen but your card is sweet enough to keep you happy for at least another year, you will only be unsatisfied with the gains you will get upgrading one gen or dual cards!

[Deleted]

Well watch dogs is coming out soon (as well as dragon age 3, witcher 3 and division in the near future) and I'm wanting to be able to run the game at (near) max settings 1920x1080 at 60fps constant with the exception of turning down anti-aliasing because it's generally a hog with very little gain. If Assassin's creed IV is anything to go by then I'm going to need an upgrade to achieve that. I'm going to be buying the 670 off ebay most likely where you can get it for around 150 pounds (no warranty doesn't concern me), I don't think I'm going to be able to get a cheap 780.

Are two 670s going to give less than one 780? doesn't seem likely but maybe you have benchmarks that say otherwise. I'll look into it more.

Edit - It does seem like the hassles of sli (power consumption, micro stutter, sli support) may make it not worth it and it would be better to just sell my old card and upgrade.

[Deleted]

GTX780 should be able to run it with zero problems at 1080p - the question I have is, 'Do you have the 3570K CPU?'

[Deleted]

Sadly no a mistake on my part, when I bought it I was thinking I wouldn't overclock but in hindsight I should've.