Gary Scotland wrote:
Thanks for your reply, much appreciated.
I forgot to say that I'v tried many SATA lll SSD's and none were recognised by the G5.
SATA 1 hard drives work no problem, but they are no longer available, hence the need for an SSD.
Im in the UK and no one sells OWC here, including Ebay.
A SATA III hard drive should work without issue, but you will need to find a smaller sized drive since I would imagine the G5 won't be able to access an internal drive larger than 2TB. It has been so long since I used a G5 that the maximum drive size could be much smaller. The more recent drives have also changed their default block size from 512 bytes to 4,096 bytes so that drives larger than 2TB are possible, but even smaller drives can have this larger default block size. The drives usually keep the 512B block size reference for backwards compatibility, but it still might cause problems with such an older system.
As for the SSD not being recognized, it could also be related to this default block size.
Here is an article which provides more details about the 512B to 4K block size used by newer hard drives and somewhat applies to SSDs.
Im afraid I do not understand this sentence:
SSDs need to partitioned on 4K boundaries (usually the partition starts at 1M) in order to get the best performance from an SSD, otherwise the SSD can be as slow as a hard drive.
If you could rephrase in everyday language that would be apreciated.
It is a bit hard to explain, but the internal structure of the SSD NAND memory is organized into 4K blocks. All data internal to the SSD requires saving data in 4K blocks. If the partitions are aligned on the 4K boundaries, then it matches perfectly with the internal drive structure allowing for faster (optimal) writes to the internal SSD NAND memory. If the partitions are mis-aligned, then it requires the SSD to work harder to save the data. Aligning the partitions also prevents excessive wear on the SSD.
Here is an excellent article detailing the performance benefits of proper partition alignment for both hard drives and especially SSDs and does a much better job than my attempted summary.