From "Hot Deals"... "... In a laptop, the performance boost when replacing a 2.5" hard drive is huge, often around 6 times faster. In a desktop, the performance gain over a standard hard drive may only be about 2 times faster. Although random seek times will receive a huge performance boost, which means large, complex applications, such as Photoshop and Word, typically load about 10 times faster on laptops & desktops....
A lot faster, especially when you run in Raid 0. I have three Intel 40g SSD in raid zero. My average read speed is 577.4 MB/ per second Download this free utility at HD tune and see what your read/write speed is. http://www.hdtune.com/
That is if you have all the latest hardware already. If you are still running Core 2, Sandy Bridge i5 or i7 will be a massive performance boost too. The problem is from SSD you have significant performance gains only in a few very specific areas like the time it takes the PC to boot, compiling very large software projects and video encoding. For typical office or trading applications you will most likely not notice any difference.
Platter drives can also transfer some vibration to the case which may result in some mild buzzing sounds. Platter drives sometimes have a high-pitched sound which can be annoying.
I replaced HDD with SSD (Intel X25-V) in wife's notebook.... CDM Values... HDD 52.6*/52.9 28.5/34.6 0.485*/1.03* 0.98/1.06 SSD 186*/42.3 157/44.8 21.85*/41.7* 129.2/43.5 Results will vary depending upon the speed of the SATA controller. The most important values (*) for overall, general performance are "Sequential Read", and "Small File Read/Write" Wife said, "Wow! It's much faster now".
Right now using the on board Intel ICH9R controller. To manage the drives I use Intel Rapid Storage Technology. This is all you need if you stay under 4 drives. If you want to go above 4 drives use the LSI 9260 8i raid controller. They run sort of hot and cost $500.00. This is hard core, but very very fast. You give up your ability to trim you drive in raid configurations. So far I have not noticed any performance loss after 6 months in raid 0.