There should be NO guesswork regarding the RAM. It should always be installed in exactly Matched Pairs. So if one is Corsair, the other one should be exactly like it.
NO variances are allowed here!
Three gig's of ram may be ideal for Vista, but not mandatory. I've run Vista Ultimate on just two gigs and it runs just fine.
If you use a plug-in Video card, the on-board video must be Disabled in the bios.
Power Supply Wattage?
Don't be misled by the wattage printed on the outside of the PSU. That's the maximum peak wattage the supply is capable of producing, during the one second or so that it takes to start your fans, drives and charge the filter capacitors on your motherboard.
The 'all day' operating wattage can be significantly less, by as much as 30%.
On some cheap supplies, it's even worse!
I just upgraded my own PSU to an "Antec Earthwatts 650".
I previously had a much cheaper 450w supply. I've recently added several new pieces of hardware that all want their share of the PSU, so this new one with three 12v rails, will fill the bill.
You can't have too much power, but you sure as heck can have too little!
On the Video Card fan issue..... I just found an AGP video card in my junk drawer that I wanted to use, but the little fan was frozen solid. (would not turn)
I removed the fan from the heatsink and cleaned the fan and heatsink, then I injected some high-grade light machine oil into the bearing on the back of the fan,
with a hypodermic needle. After spinning the blades by hand for a few minutes the bearing freed up and the little fan now runs like a new one.
That little video card is now running just fine, in one of my test machines.
Many of those little video card fans are so cheap that they will only run for a year or so without maintenance. (clean & oil)
I clean and oil all the fans (9) in my main system about twice a year, to keep everything running smooth and quiet.
Never overlook the obvious.....a stuck Video Card fan, or CPU fan, can shut you right down.
Likewise, dirty ram will also fail.
Ram usually sits right next to the CPU and gets blasted with dirt, from the CPU cooling fan. The dirt can short out the little legs on the ram chips, causing ram failure. It doesn't take much!
I've saved hundreds of sticks of ram over the past 28 years, by just washing it.
Likewise the ram chips on video cards. I'm still using a video card that I had to wash about 4 years ago.
I hope all this helps someone....somewhere.:D
Cheers mates!
The Shadow
