Hello, I successfully did 6GB RAM .. Crucial M4 256GB SSD into main sata2 position .. and Seagate Momentus 750GB 7200rpm 2.5'' sata hdd instalation using pata to sata hdd caddy bay instead of pata optical drive upgrade .. both configured as 1TB fusion drive.
Few recommendations after my upgrade..
- If not sure which ssd to buy, pick one with marvel sata chipset (samsung 830 series, crucial m4..). They seems more compatible with older iMac's
- I wasn't able to fix my ssd inside the same way that my older 3.5 inch drive was. Even with crucial 3.5 to 2.5 extension. Extension was short (4inchx4inch, but usual 3.5inch drive is 4inchx5.75inch) and even with longer extension, imac's sata cable is too short. Strong thick double sided tape on back of imac did the job in ideal cable position.
- Attaching a thermal sensor from optical drive onto a Momentus drive was bit tricky.. because you have to put it on top of the drive, instead beneath, as it was attached to optical drive. There might not be enought room between new drive and display panel. So get rid of sensor capsule and just tape the sensor onto the Momentus drive.
Write speed ~210MB/s .. (~45MB/s before upgrade)
Read speed ~260MB/s .. (~55MB/s before upgrade)
I do recommend this upgrade :)