Posted By
MMS
on 2020-05-01
11:45:46
 |  Re: Overclocking PAL 264s
THX !
OK, so some speed test on emulator (unfortunately I have no 1551).
I choose Csory's Elite, it is 205 blocks long, very close to the 203 block long PRG used for testin on C64 Jiffy.
It would be great to test it on real config, but currently have no time for that.
So loading times of 205 (203 n C64) blocks as per my own measurements and available doc.
Certainly it has a +/- 1-2 sec deviation, proper starting and stopping, so 1541 loading of Elite +4 could be 125 secs, not 127 (all tested two times, but eh...)
C64 stock 1541 (203 blocks PRG loading): 124 sec
C64 Jiffy 1541 (203 blocks PRG loading): 12 sec This is the 10x factor.
Plus/4 stock 1541 (205 block PRG loading): 127 sec (YAPE1.1.5)
Plus/4 stock 1551 (205 block PRG loading): 63 sec (YAPE1.1.5) - (...) and not 4.5x as stated (correction: few years ago clarified it is 2.2x only)
Plus/4 stock 1551 (205 block PRG loading): 64 sec (YAPE1.1.5) - (...) and not 4.5x as stated (correction: few years ago clarified it is 2.2x only)
Plus/4 Csory 1551 V4 (205 blocks): 6.1 sec :-O (YAPE1.1.5) - with Csory's fastloader the 1551 is 20x faster, than a stock 1541, and 2x faster than Jiffy. WOW!
Plus/4 Csory 1551 V4 (205 blocks): x.x sec (Plus4emu 1.2.10) - with Csory's fastloader 1551 emulation crashed with BREAK ERROR...
Csory's V4 fastloader (with switched off screen) clearly shows what does 8 bit parallel loading means, 20x of the speed of stock 1541 on IEC.
Loading 205 blocks in just 6 seconds! THIS is impressive! Evidently much better than Jiffy.
On the other hand the emulated stock 1551s in this test showed only 2x speed increase compared to stock 1541 loading, on both emulators I use.
Updated remark here: IEEE-488 floppy drives from C= on the same 8bit data bandwidth are 4x faster than IEC
These results surprised me a little.
-16-20 sec loading time (6-8x) is what I would expect from a stock 1551, with 8x more data bandwidth (data bit), but we know, it did not happen.
-2.2x faster speed is less impressive, but still a noticeable increse compared to 1541
-2x speed increase with 8x more data lines is not so impressive, so maybe only an emulation bug.
Maybe it is only an emulation issue, but as both emulators I used for the testing showed almost the same result with stock 1551...
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