Your rig is almost exactly the same as mine :) (except the graphics cards)
anyway.. Adding a better CPU or More RAM will not increase your 3dmark scores that much.. what WILL increase your benchmark will be the speed of your memory.
Now you have Corsair XMS, which - is very good memory, however it doesn't run at very good latencys..
You'd want to be running memory thats of as lower latency as possible, this will dramatically increase your scores over any other hardware change.
Your Corsair XMS is good memory, but it will only be running at: 1T-2-4-4-8 if your lucky, what you want is some GSkill PC4400 which will run @ 1T-2-2-2-5 @ 250-280FSB (allowing you to keep the low latency memory whilst overclocking it.
A RAM’s CAS latency consists of 4 numbers, such as 2-2-2-5, which correspond with CAS – tRCD – tRP – tRAS. Your memory essentially is split into four parts, CAS - tRCD - tRP & tRAS, each of these allows the memory to communicate to different components in your computer.
CAS stands for Column Address Strobe. This is the number of memory cycles that pass between the time a column is requested from the active page and the time the data is ready to send across the bus. This number is usually 2, 2.5, and 3, on DDR memory. This is actually the last part to come into effect.
RAS to CAS Delay is referred to as tRCD. This is the delay in memory cycles between the time a row is activated and when data within the row can be requested. This only happens when data is not on the active row.
tRP is the time for RAS Precharge. This is the time in memory cycles that is required to clear out the active row out of the cache, before a new row can be requested. In other words, it’s the time it takes for the memory to stop accessing one row and start accessing another. Once again this only takes place it the data is not in the active row.
tRAS refers to the minimum time that a row must remain active before a new row can be activated in each memory bank. A new row can not be opened until the minimum amount of time has passed. If there is more than one bank on memory, this will help the performance of the tRAS. If there is only one active bank, then the need to change rows is guaranteed, and if there is more than one bank with memory, then there is only half the chance that there will be a need to change rows. In turn, the tRAS will only come into effect half the time. The tRP and tRAS together are often referred to as the Row Cycle time, because they happen together.
Corsair XMS PC4400 will run at 1T-2.5-4-4-8 or something, most likely higher latencies as your FSB is quite high, and the higher the FSB the slower the memory latencies typically are.
Now the fastest memory on the market is GSKILL, you can find it @
www.overclockers.co.uk or other similiar retail stores (i recommend overclockers as they are great quality and competatively priced).
You can buy GSkill PC4400 or GSkill PC4800 DDR1 / DDR2 that runs @ 2-2-2-5 @ 260FSB or faster, alot of the time, if you have a DFI board or an Asus board a motherboard thats a good overclocker, you can force the CAS latency to 1.5 or 1!
I would recommend if you really really want a big difference to sell your XMS and buy some Gskill. You will notice a huge difference, + it will greatly improve loading times.
Essentially now a days the performance of computers are not down to clock speeds but down to low memory timings, hyperthreading and memory cache of the cpu.