I post on the Announcement thread but didn't any response. So here I tried again.
Excited by the RAM disk performance boost, I did a quick test but found out higher Benchmark has nothing to do with my real-work performance experience.
So I tested on two machines, A: Intel core i5 4 cores + 16G ram with Win7 and most recent PI, and B: Intel Xeon E5506 2.13GHz 2 cpu 4 cores each + 24G ram with Win7 and recent PI.
Machine A benchmark result= Total:1895, CPU: 4043, Swap: 594, Trans: 107.25 MiB/s
Machine B has 8G RAM disk (softperfect) and the benchmark results:
No Ram disk= Total:1672, CPU: 3975, Swap: 494, Trans: 89 MiB/s
8GB Ram disk, listed x1 as Swap space = Total:4081, CPU: 4020, Swap: 4368, Trans: 788 MiB/s
8GB Ram disk, listed x2 as Swap space = Total:4369, CPU: 4017, Swap: 6848, Trans: 1236 MiB/s
8GB Ram disk, listed x4 as Swap space = Total:4610, CPU: 4148, Swap: 8550, Trans: 1544 MiB/s
8GB Ram disk, listed x6 as Swap space = Total:4448, CPU: 3962, Swap: 9060, Trans: 1636 MiB/s
So it seems that Machine B will easily out-perform machine A with increasing margin as RAM disk being added in and also starting using the parallel swap space feature. However, when I did a real-world test with my image (a Ha frame shoot by QSI683wsg), just doing normal MLT, multi-iteration HDR, and StarMask, I found that Machine A ALWAYS finish the task faster (eg. 3s vs 5 s, 7s vs 9s, 10s vs 13, 5s vs 9s) no matter I use parallel swap space or not. So the real-world test shows the similar benchmark result when NO ram disk was added.
Since I was about to build another new machine so I was hoping to use this test as a guideline for CPU, memory, and SSD decision, but now I am really confused.
Why such discrepancy between benchmark and real-world performance?? And why RAM disk does not help? My guess on this one was that with core i5 limited computation power, the Ram drive (cost CPU) does not directly beneficial in the real-world experience and hence CPU performance is still dominating. Maybe a core i7 may have enough power to see the benefit of Ramdisk???
