Reporting to you about my new SSD Upgrade for my Power Mac G5.
A month ago I bought a Transcend Solid State Drive 2.5" 64GB SATA MLC, Model "TS64GSSD25S-M". It is installed in upper bay on internal Serial ATA channel of my PowerMac G5 Dual 2.5 GHz (June 2004). From first installation it works great! Its fully recognized by Mac OS X 10.4.11 Server installed on it. Still stable in work use since the installation.

The problem with installing in a 3.5" bay is the small size of drive (2.5"), so I bought a Scyth Quiet Drive box for 2.5" drives. (I think it's this Scythe "Quiet Drive for 2.5" Internal HDD Silencer for 2.5 inch HDD ($37.90 list))
Picture: (Excuse quality - photos taken w/iPhone)

I added the Apple logo sticker to the case. :)
Anyway it fits in Power Mac G5 without any issues, but cables do make some mess in front of drives.
(FYI - for my 2.5in SSD adapter (for 3.5in HD bay), I bought the ($24.99 list in 2009) ICY DOCK Screw-less 2.5in to 3.5in Case. It makes for a cleaner install (no cables) as it has std SATA HD connectors in the same location as a std 3.5in SATA HD. SSDs don't really need vibration dampers, etc. There are cheaper adapters available, I just liked the ICY Dock design.-M)

In OS X it's recognized as usual:

Performance Tests show some improvements compared to my old Western Digital Raptor ADFD 74GB. Here is Xbench results:

It utilized 2/3 of SATA interface without NCQ. It only trails the Raptor in Sequential Uncached Read. Why some of tests are low? I think because of G5's SATA-I interface with TCQ only and this type of drive is Multi-Level Cells, in fact slower than SLC version of these Drives. (Not sure what controller this SSD uses but it's spec'd at Max Read 148MB/s, Max Write 92MB/s for the 64GB model (per mfr's specs). Some MLCs are very fast (with SATA II interfaces) - 200MB/sec or even better specs - larger capacity drives are often faster than smaller ones. (My Crucial M225 (barefoot controller based) is spec'd at 200MB/sec write/250MB/sec reads w/SATA II interface) - although the downside to MLCs are finite write/erase cycles (but much lower cost than SLCs). And SSD performance degrades over time/use (writes/deletes, etc.) without Garbage collection or TRIM. (Unfortunately no OS X support for either of those to date, no utils for OS X, etc.) But even then SSDs still compare very well to std HDs even in writes and random access/reads are typically much faster.-M)

Pros: It is fast, really FAST! Applications load faster than from the Raptor, Mac OS X boots much faster (8 seconds vs 20 seconds on old drive), no noise, no high temperatures, low power consumption (5vDC 0.3A vs 5vDC 0.9A, 12VDC 0.75A on my old Raptor), light weight - only 55 grams vs any classic 2.5" hard drive.

Cons: It still expensive in 2009. I bought 64 GB for $250.

I recommended it for those users who want to gain more speed to work in applications and for those who don't like noise.
-Viktor D.