How to monitor HD use? PCIE SSD vs Sata raid 0

Well i am working in a not so rich university. and as i sayed budged is an issue. We can spend 250 euro for a revo drive, but what do you think a ddr3 system with 256Gb ram would cost?
For problems that exceed your ram size, the relative ram size, and hd speed are much more critical then the memory speed. Because the HD becomes the bottleneck. Do you have matlab or octave? just invert a matrix that is larger than the size of your RAM, and you can test it yourself. I am quite sure our old dual quad xeon E5472 3GHz. 1600MHz fsb, with 64Gb 667MHz ddr2 still beats a flashy new, 16gb ram ddr3 system. (provided they have the same mechanical hard drive). So to respond in short, yes winning the lotery and spending lots of money would solve the problem, but since we are on a budged, i am looking for help on a cost effective solution.

Thanks for your reply.
1) I think Raid 0 for a scratch drive is perfectly ok! there is no critical data stored there its just for temporary data, during the matrix operations. It is just like setting your windows page file on that raid0. The worst thing that could happen, is that you get a bluescreen, and you had to restart your computer. All crucial data is stored in a save place, dont worry. Sorry if that was not clear. Thanks for worrieng so much that you would fire me, for that.

3) I completly agree, just the budged doesnt cooperate, its not really the fold of my boss/professor.

2) This is what i would like to know but then in hard, (or if necessary soft) numbers.

For example the revodrives have excelent speed but especially when the data is compressible.
Random write performance is not so much better than a normal ssd, or a ssd raid.
How can i find out how the hard drive is used during the calculations? I mean it is difficult for me to determine wich of the specs are the most important for this type of applications: sequential read/write speed?
random 4 KB read/write speed? Iops? Raw transfer rates? How compressible is that temporary work data? I mean i can theoreticaly save it on disk and zip it, and see the data reduction, but i dont think that would be really representative for the type of compression used here. Is there any further advantage of the PCIE drive being on the bus, and not behind a sata controller? How are windows or linux using the HD when they are using it as an pagefile/swap partition? are they writing little bits, as they come from the processor, or are they stockign up the little bits into larger chunks in ram, and then write them to the disk? can i influence how they handle this? can i measure how they handle this?

I was kinda hoping that there would be a disk monitor software that would tell me how the drive used during my use such that i know wich of the benchmark criteria i should prioritize for a particular use.
Anoter simple solution would be if they would have a remote machine for rent/trying, with a revo drive such that one could test it for a particular application.

Thank you for the suggestions. Especially asking to some local businesses can be a good idea, but i fear they are not swimming in money and hardware to. Believe it or not, this system is actually already bought used.
3 server blades, 8 xeon 3.0 GHz cores each 32 gb each, for a total of about 1000 Euro (1.5 years ago, it was the best performance for the buck that we could find on the budget). Honestly they are old, but they have about 80GFlops per machine, newer i5s dont do so much better. This year we went wild, and there is a used gtx titan comming, for gpgpu programming When i sayed buged i meant like a 1000 Euro a year . Many of the guys here even bring in their own money, we were even thinking about doing collections in town. Maybe poverty in some ways stimulates creativity, but it also takes a lot of time.