My thoughts on CF vs SD performance:
Compact Flash:
I classify things into three rough groups
- Industrial CF (Firmware > 2008) tuned for small files. Some are tuned for writes, some are tuned for reads, but they all work pretty well. Latency ranges between 0.3ms to 0.6ms. Transcend 44pin Pata SSD and 40 pin DOM devices perform similarly to this group because they use similar flash and flash controllers, just in a different form factor.
- Camera CF's tuned for different operating modes. True IDE performance seems like an afterthought on these devices. Latency ranges from 0.5ms to 7.0ms. WMDA is often not supported.
- Old CF's (Firmware 1995 - 2005) Thing like the Western Digital Silicon drive were pretty cool in 2002, but the flash and flash controllers used in these devices are noticeably slower than stuff that came out a few years later.
Within each of these groups, there's still a wide ecology of controllers, firmware & flash. The best are great. The worst are not as great for anything other than DOS & Win 3.1
SD-IDE bridges
There's pretty much only one game in town these days and that's the Sintech devices.
- Good latency. 0.3ms to 0.6ms range depending on your SD
- Similar performance regardless of what SD you use because the bridge talks to the SD card at the "High Speed" standard from 2003 which limits transfer rates to 25MB/s.
- Supports WDMA with most EIDE controllers. Sometimes early EIDE controllers don't like these devices (CMD640?)
- Doesn't have a full LBA48 implementation so using storage > 128GB will result in problems.
The uniformity of these devices is kind of a benefit. You know what you are going to get.
The other option is a bridged Sata SSD.
- Great latency. 0.15ms to 0.3ms
- Transfer rates that saturate any PATA mode
- Outside of certain Marvell bridges, WDMA modes won't work
There are some performance differences between buffered and non buffered SSDs, but it's less noticeable when using a PATA bridge. You probably want to go this route for things newer than Win98.
Which is best?
Much of it depends on your computer and IDE controller. The same device on a different controller can produce different results. Here's some generalities:
- I have an ISA controller! You probably have large enough CPU bottleneck that you can only tell the difference between the solid state storage device families when using a benchmark.
- Mid 486 VLB PIO 3 to Pentium II UDMA/33 controllers: Camera CF's and Old CF's can feel slower. Everything else is competitive unless you are having WDMA issues and that's complicated.
- Pentium III UDMA/66 and faster: Sata SSD's start to pull ahead of everything except for the very best industrial CF's & DOMS.
https://www.vogonswiki.com/index.php/Storage# … Retro_Computers