Implying it doesn't:
CPU speed plays a large role in random IOPS. Which is what happens when you are randomly streaming content off a drive. Having a slow processor, such as a low end AMD chip, WILL slow an SSD's performance down even if it's connected to a SATA 3 bridge. You better believe that. And the Cell processor in the PS3 is old, older than old. It's definitely a major part in limiting the SSD performance in the PS3.
Edit: Also if you don't believe CPU has any impact on SSD performance, and you have a processor that is capable of downclocking when idle, go ahead and set the max frequency of your chip to it's low clocks. If my 3770k is sitting in it's low power state of 1.6Ghz, my SSD performance gets cut in half. Imagine the impact a low frequency would have on a sh*ttier chip?
That's more to do with program access and start up, which IS CPU based, if I half my CPU speed, ANYTHING will take longer to start up, but that's not to do with the hard drive or the RAID, that will still get the data to the core as quick as it should, it'll be the CPU then lagging behind to process that data quick enough. An SSD will fully flush as much data into the RAID as it possibly can (e.g., if the connection is SATA2 based, then it will fill that pipeline, same goes for SATA1).
What you're subjecting to CPU based there is calculation of how quick it can deal with said data, it doesn't make the SSD or Hard Drive faster or slower, they will still fill the RAID's at the same rate they've always gone. For example, the Anti-Virus example given, the SSD is going faster at scanning through the listings, faster than the CPU can keep up compared to a standard scan, it's akin to having a brick of data thrown at it and being screamed it CALCULATE THIS LIST CHECK NOW I'M DONE! When scanning normally, it's slowly working its way through the file listings, which can be anywhere, but lets say most basic scans will take a gander at around 6 to 9 thousand files, as a scan takes place it will be crossing like 100 to 200 files off at a time, with an SSD, it will be throwing the name of all 6 to 9 thousand files right at the Anti-Virus to clear it through the CPU.
As for the CELL, it's working with a SATA1 Bridge and installs takes seconds, it's not exactly THAT limiting when using an SSD, considering how the OS on a console has to keep these files in check and is optimized for slow ass 5,400rpm, anything over will just make that a breeze for the system.
Basically, the barrier for SSD will always be the SATA bridge, that's the important one, but SSD's are backwards compatible so they WILL fill the bridges of the older models to still provide a massive speed boost. The CPU stuff, we're talking like small time and gains here in terms of Hard Drive speeds, the hard drive/SSD will always provide at the best speed it can, HOW that data then gets handled and processed is a different thing.