just for a frame of reference, the fastest hard drives on the market today can sustain reads of ~55MBps - 60MBps (that being the aforementioned Quantum Atlas) in single drive config (with the necessary Ultra3/U160 adapter). with enough of these drives in a U160 RAID array, you could probably reach 80% - 90% of the max throughput of your adapter (160MBps...... and thats if you have a 64bit PCI slot. unless you have a very high-end server-set motherboard, which the vast majority of consumers do not, you would therefore limit you to ~1/2 of the max potential throughput of the adapter - due to it being frorced to run in 32bit mode. this is a very common oversight of normal consumers). bear in mind you would also need a 64bit capable OS, but it looks like you will have that covered.
so lets just say you have in your hands a board that has the required 64bit PCI slot and you slap in the desired U160 RAID adapter and 4 drives in RAID 0 (we wont go into mirroring, though i would highly suggest it since you will have critical data stored on them...... if you are not hip to what RAID is or how it works, here's a good explaination......
http://www.acnc.com/raid.html ). now lets say you are getting the optimal throughput your disk i/o system is capable of..... something like 150MBps - 155MBps.
thats really moving. and due to SCSIs typical ability/feature of multithreading, the disks and controller will be able to process multiple read/write requests at the same time (something IDE drives cannot).... this would translate into disk i/o that would be mind-numbing..... in a good way, of course.
now lets look at SDRAM's capability. with a high-quality chipset and high-quality RAM modules running at 133MHZ, you could probably reach upwards of 450MBps - 500MBps. half a GBps is not too shabby. comparatively speaking its smokin' (compared to mechanical/magnetic media such as a hard drive). if you have two separate memory channels (one for each processor), you could effectively double that given the right scenario. i have my RAM running at 143MHz, and get about 595MBps to 630MBps depending on exactly what operation type we are referring to.
i will submit that a RAMdrive will probably not be able to reach the real-world performance dividends mentioned above (due to process overhead and such), but there would most likely be a night and day difference between it and a single hard drive or RAID array.
