Right, spec in the sig and I suppose this is the right subforum to ask..
Droping 4870x2 for a 6870 - will make the job easier,
Anything to reduce heat and power makes quietening a pc easier.
I'm guessing your a gamer - do you game at night?
Have you tried over ear headphones? (The cheapest way to silence a gaming pc)
How can I make my PC as silent as practically possible - I guess watercooling is the way to go?.
Not always. depends on what you use the pc for and when you 'NEED' the quiet.
From your replies it's the fan cooling the cpu that the issue.
Change the cooler to a twin tower type (you might not need a fan)
If you do heavy cpu stuff strap on a TY-140 (running at a constant speed)
Or get a Thermalright Venomous X Silent / silver arrow (for set and forget quiet)
Swapping to a Accelero S1 PLUS + fan and fan controller (silent with 2d apps
quiet when gaming)
Or a Accelero Xtreme PLUS II (for set and forget quiet)
Please advise with links/tips or suggestions, I work a lot at it and it annoys me late at night when it's fans are whirling due to bulldozer's stupidly high temps on idle..
For £90 You may find that's all you need - and if not you can sell one or both without losing to much cash.
Your case and psu are not really inaudible watercooling friendly.
Easy enought to set up a constant low rpm fan cooled loop for cpu & gpu.
(well within budget especially if second hand)
I'd always advised a universal block for a quiet loop so that saves some cost - especially in the longer term.
But a passive tower and active gpu cooling (water or air) is normally always a good start, when quietening a gaming pc.
After you'd got an inaudible cooling solution for your cpu and gpu, you realise how loud all the other stuff is...
So for almost every one a least 1 quality fan is needed - 3 max in a quiet build - these 'hide' the other electrical / mechanical wines and clicks with a soft hum
