Prebuilt looking for upgrades.

The RAM is fair.
Q9550 is good still.
Motherboard isn't the best, but don't know all the specifics.
That PSU isn't very good, I think you should get a good Corsair, OCZ, Seasonic or XFX.
OS is fine.

Sorry but I don't know what RIFT is or DCUO, please tell.
Also, the GTX280 is hardly outdated just yet, if you're sure you want to upgrade then I personally think the GTX460 or 560 would be the better choice for your needs.

A new card would help; also do you have a 64bitwindows? If so you could stick in more ram.
Otherwise your system is plenty fast enough.
Might be wise to reinstall windows if you're still not happy (don't know how long it's been since the last time but prebuilt systems can have allot of crap on them).

EDIT: I'm also not sure about the psu please check if it has enough connectors to support the new card.
otherwise it might not be the best but if it can handle the nvidia card I see no need to upgrade it.
Also try reading some reviews as to decide what card to choose.

You probably already know this mazsta but connectors is the least of importance when getting a new graphics card. Check that you have enough amperes and enough wattage to run it. Also, two molex power connectors (4-pin peripheral) can be transformed into 1x PCIE connector. Although I really would recommend a new power supply if planning to upgrade to a fermium card on a Dell.

However, if you don't want to then you could always opt for the ATi/AMD counterpart, they usually have lesser power consumption.

If the power supply unit's model number is the D750E-00 then it will do just fine. There is absolutely no reason to replace it except if it's defective.

The OEM for the D750E-00 is Delta a very reputable PSU manufacturer. There should be four 18 Amp +12 Volt rails with a claimed maximum combined power of 732 Watts. It should have at least two PCI Express supplementary power connectors.

A referenced clocked GeForce GTX 570 will draw a maximum of 18.25 Amps from the +12 Volt rails and requires two 6-pin PCI Express Supplementary Power Connectors from the power supply unit.

Your current power supply is more than sufficient to handle the upgrade and any CPU & GPU overclocking.

The way a bench tech would go about answering your question would be to identify your "bottlenecks", and alleviate them one at a time, until you are happy with your final performance and don't want to invest more money for only moderate subsequent gains.

The problem is, where to start?

I do agree, your PSU should be the first thing to replace, since it has had a long life, and newer/more powerful hardware will require more power.

I would try a GTX 460 next, not too much money, and it won't "outleap" your existing components' ability to task it. If you went overkill with an awesome graphics card, then you have to deal with an extreme "bottleneck shift" and you might as well replace your mobo and cpu to keep pace.

How do you identify your bottlenecks? Do you benchmark or just look at each piece of the computer seperate and go from there?

As I alluded to, it's easier if you have a bench tech do it for you. I have a lab setup to do some testing of my own, like this:



For video rendering performance, you swap out the graphics card, run something like Cinebench 11.5, try another card, then another. At one point, it won't make a difference if your using a $180 card or a $500 one, and at that point, you have alleviated the GPU bottleneck on the system, and you can go with the slowest/cheapest card that gave you the latest noticeable or worthwhile gain.

Next, you try different processors with same mobo and original graphics card.

Next, you test combinations of the two.

Somewhere along the line there is a small change in price and a big change in performance. Likewise, there is another point where there is a big change in price and a small change in the "next highest" observed level of performance.

These price/performance changes make it easy to see what your best bang for the buck is.

Thank you for your information  

Most people don't have a whole range of graphics cards to test with so that kind of testing is ludicrous.

Run the applications that you usually use and monitor the CPU and GPU load using a utility like Lavalys Everest Extreme or AIDA64 Extreme edition.

If the CPU load is pegged at 100% but the GPU load isn't then you are CPU bound and a CPU upgrade will gain you some performance.

If the CPU load is less than 100% but your GPU load is pegged at 100% then you are GPU bound and a GPU upgrade will gain you some performance.

Well, his questions was NOT

"How do most people test for bottlenecks..."

It was HOW DO I TEST FOR THEM.

I answered his question the way it was asked.