So I just saw a deal for a r9 290 for £305 which is pretty normal but it comes with free AMD 8gb gamer series 2400mhz ram. That's worth £90 on their website and and cheapest I seen it was for like 80 on ebay. I think I might wanna buy it then sell the ram on ebay or something but I don't think my PSU is good enough. So the 290 say 750w minumum although I've seen allot posts about people being able to use it with 650w powersupplies. Do you think this would work with my XFX 550w 80+ Bronze power supply. I feel like 550w is pusing it....
550w imho is pushing it as well. Stock speeds/voltages and no synthetic benchmarking yeah it may be hovering about the 400w'ish mark but run 3dmark.... yeah its gonna be high. Now add any oc at all and you'll be exceeding that figure for sure. I would look at a eg. xfx750w (or more) that way you'll have a bit of headroom after overclocking shenanigans. Stick with xfx - price point and seasonic as the oem you cant go wrong.
The issue is not that it can't but when it can't. When pushing a psu 90% plus the power is no longer efficient. Lack of power kills hardware. May have issues in the future or you may not. That's why a lot of veterans purchase over kill psu. When it comes to efficient power don't cut corners. Better to sell you psu purchase a 750 bronze psu at the very least imo.
Totaly: 150+75= 225W + 75 pci-e power = 300W which the card will never use, cause there must be some kind of safe margin.
The card can never use more power, then its get delivered to, so thats why most of those reviewers are so hillarious, cause wenn it comes to power consumpion of cards, most seem not to have any idea what they are talking about.
I use an MSI 290X gaming on a 500w coolermaster bronze psu. The card doesn't draw enough to turn it off, and it runs at 1040mhz with no issues or throttling. I use it with a 4 core 95 watt tdp processor, 4 hard drives, 2 1600mhz ram sticks, and 5 case fans.
It depends on how you use the card. I use mine mainly for gaming. If you're gonna do mining, benchmarks, and other intense loads then maybe your psu won't hold up. Power is not consistent, while the pins are said to be limited, and typically are safeguarded by a lower wattage, you can push more through them. A psu's rated power isn't its maximum either. A good psu can usually go 100-200 watts above its rated power for short periods of time.
Jonnyguru is decent at measuring most factors. Suppression, limiting, ripples, rails... The list goes on. Check out the manual on your psu and some reviews where they actually test it thoroughly, if you are that concerned. It should be able to power the card with no problems though and if you don't push it to the limits it should last you until you need/want to upgrade.