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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Morley on June 03, 2004, 08:50:33 PM
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Just a quick question...
How fast is really the A4091 SCSI controller? I'm using the internal one on my A4000T, and I can't get more than directly below 8MB/s at max.. and this is from a 18GB USCSI drive that really should be faster than this.(I expected it to stop at about 10MB/s which is the FSCSI2 maxspeed...)
Is it the Zorro-bus that is the bottle-neck, or? I'm also using a poor old C=3640 as CPU, maybe this is the cause...
Or perhaps I should be very satisfied with these results. Gimme your benchmarks please!
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You get 8 Mb/sec ??? I don´t know of any benchmarks of scsi, only ide with a Powerflyer and this on a 68030, but your 8 Mb/sec sure does look good !!!
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Well, since it is a DMA controller, I expected it to go very near the 10MB limit of FSCSI2, with a fast disk. But maybe in reality it is not posssible?
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8MB/s is pretty good. What program(s) are you benchmarking with. I can run it on mine to see what kind of speeds I get.
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I'm running the benchmarks on Sysinfo, using FFS as filesystem(doh). Filesystem shouldn't matter though on raw reads I suppose.
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I'm getting about 9MB/sec, if I start SysInfo right after SetPatch (I remember it being a bit higher even with FastRom enabled). Unfortunately, the duration of the benchmarking process is much too short, therefore the results are a bit inaccurate. After booting the speed is still around 8.6-8.8MB/sec. The harddisk is an IDE drive connected through a IDE->SCSI adapter. I do think the onboard SCSI controller performs very well and close to the theoretical limit.
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hi all,
i have an A4K 040@25mhz, 2 mb chip, 16mb fast, buster 11 and an A4091, i don't understand how you guys are all pushing between 8/9mb/s when i can only get 4.2mb/s.
what is wrong with my setup? is there something i'm doing wrong?
cheers, JuvUK
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You never get close the theoretical maximum; my best speeds with Blizzard SCSI were about 8.5 MB/s - but older drives did about 6 -7.
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is there something i'm doing wrong?
cheers, JuvUK
Using Synchron mode?
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i'm at work at the mo, but i will check the jumper setting tonight (as i can't remember) but would Synchron really give me an extra 3.5-4mb/s extra transfer speed?
8mb just seems a bit high
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Hey Juvvy!
My Bliz PPC SCSI & FastATA both give 4.2mb/sec I think its MaxTransfer related as all my CF's and HD's are the same and all were setup the same on Classic Workbench OS3.9
Steve.
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hiya bud,
i'm using a SCSI hd not a cf, i was quite happy with the 4.4mb/s until i saw this thread, i mean there's a BIG difference between 4.2mb/s and 8-9mb/s, and i just wondered how they are getting these speeds?
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hiya bud,
i'm using a SCSI hd not a cf, i was quite happy with the 4.4mb/s until i saw this thread, i mean there's a BIG difference between 4.2mb/s and 8-9mb/s, and i just wondered how they are getting these speeds?
Hey mate,
Not only using CF's using SCSI-IDE and 7200rpm PATA HDD at the same speeds...
Did buy a SCSI HDD from flea bay but it arrived DOA so not able to test real SCSI drives yet.
Anyway if I figure out how to unleash the faster speeds I'll let you know :)
Stevo.
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i'm but would Synchron really give me an extra 3.5-4mb/s extra transfer speed?
8mb just seems a bit high
No exact figures but the difference is noticeable, in my Blizzard more than 2 MB/s.
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syncron is on :(
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Some things i have noted on the 4091... There are a commodore made one and dkb made ones, i haven't tested for any differences between them. 10MB/s is a theoretical maximum,theres no gaurantee it will run it exactly..Your best chance though is with:
A fast 10K rpm drive rated for fast scsiII that has ample buffers on it(no adapters),Latest 4091 roms,Active terminatiors throughout,Synchronous mode, shortest possible cable.Run SFS(smart file system) and SET the max transfer correct(big one here!).althought passive termination works on most scsi,it a hack at best and something more suited to old scsi 1 imho.
The 4091 having to dma to the slow motherboard ram because of the A3640 may come into play.
Now realize alot of factors can hamper all this goodness like different buster revisions,other scsi devices on the chain with broken firmware(crappy toshiba scsi cdrom drives come to mind),old scsi1 or non fast devices,bad cables,S-L-O-W FFS!
Theres a reason that SYSINFO is called sys(MIS)info.. try diskspeed4.2 or some such for more accurate results.
Scsi is almost always better on amiga compared to ide.Scsi off a good accelerator can be night and day.. one reason the warpengine,cyberstorms,etc do so well.