Wow, nice to know that I vanish for two whole years, and not only do I remain on the list in the OP... Athanar retains the pink color I bestowed upon him, too.
i have a question
what is the difference between having one graphics card compared to 3
As a general rule, multi-GPU settings show "diminishing returns:" I.e, 2 GPUs does NOT mean twice the power, and 3 doesn't mean 50% more than 2. The exact amount of use each additional card gets varies depending upon the game (and other factors) but I believe typically ranges around 60-90%; this is usually multiplied for a third card, so if the second card boosts performance to 190%, a third might only send you to 271%. (and that's a VERY optimistic situation) Often, the drop-off for the third card is so steep that it's almost impossible to recommend such an option instead of 2 or 1 card.
Whether getting multiple cards makes sense can vary: in some cases higher-end cards start costing way more than what you gain, to the point where buying a pair of cheaper cards, even considering the drop in effectiveness in such situations, will wind up being a better buy than a single top-of-the-line card. This typically comes at the >$300US price point, where it often proves cheaper and more powerful to hook up a pair of "sweet spot" (anywhere from $100-200US, as it varies from month-to-month with releases and price drops) cards than to buy a single $400US+ card that often doesn't get even +50% performance over the "sweet spot" cards. Right now, for instance, it would appear that a pair of GeForce GTX 460s or Radeon 6850s would best a single GTX 570 or Radeon 6870 while being close to the same price. Note, again, that rarely does it pay off to buy a third card, and only in SOME situations is a dual-card setup justified: some downsides come with using two cards, such as potential problems with some games that may force you to settle with using only one card, while if you'd taken a single-larger-card setup you would've have had such problems.
Lastly, if you want a 3-display situation, as mentioned you might thus want to look toward ATi's cards for their "Eyefinity" feature. Not that models with "eyefinity" in their name are designed to support up to SIX monitors, while all other 5xxx and 6xxx cards can support the 3 you specify as wanting. A single one of those cards can handle such displays fine, including arbitrarily spanning a single game screen across multiple monitors; so, say, 7680x1600 becomes a possibility.
I just bought a PC second-hand for $550AU (so around $250-$300 US when it comes to electronics), but it turns out that a few things aren't as advertised and to get it up to spec I need a new mobo and CPU. Basically I want to know if it'd be better for me to just get a refund from him, or to put in a new mobo and CPU. If I go with the upgrade, I don't need anything amazing, would want it to be roughly in proportion with the rest of the parts but with room to upgrade a year or two down the track.
For the price you paid, you got off pretty well. The case alone is like $100US, ($180AU-ish?) and that's WITHOUT the power supply. I'm assuming it has a PSU to match... Which'd be almost as pricey.
One thing to keep in mind, though, is that the RAM it came with is DDR2... And if you're taking the Intel route, Intel's been VERY bullish on adopting DDR3. Heck, even if you decide to swap to AMD, (a lot of the Sandy Bridge controversy has soured Intel for most DIY'ers) chances are you'd likely wind up with a Socket AM3 motherboard anyway... Which again would mean buying DDR3. Fortunately, over the past half-year or so, DDR3 prices *HAVE* plumetted, dropping typically by around 50-60% versus what they were before. Overall, it'd still be in the range of pricing, provided that Australia saw a similar drop in RAM prices. (i.e, a similar 2x2GB DDR3 setup would probably run you a bit under $100AU, I'd guess)
» Fri Feb 18, 2011 11:48 pm 
