Messages in this thread | | | From | "Daniel J Blueman" <> | Subject | Re: max UDMA33 IDE performace ? | Date | Mon, 6 Mar 2000 12:04:18 -0000 |
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> which max. sustained read performace can be expected with UDMA33 ? ~33MB/s from buffer to host (- a bit for overheads etc)
> I have a 40GB 7200rpm Maxtor disk which should give min/max 16.7/29.0 MB/sec > accoring to a benchmark test in german c't magazine.
> but with DFI K6BV3+ main board (MVP3 chipset, only supports UDMA33 not UDMA66), > AMD K6/2-400, 128MB PC100 ram, 2MB L2 cache only get ~11-14 MB/sec read rate. > I noticed the "maxDMA=0(slow)" in "hdparm -i" output but can't find any > hint how to change this. > > is there any chance to improve/tune performace, or is UDMA33 the real limit ? > do I need UDMA66 for 20-30 MB/sec ? why?
Hi Harold,
It looks like you may need a newer version of hdparm to identify the DMA mode as UDMA2.
I've found the IDE subsystem under linux doesn't perform upto platter speeds on high-end IDE disks. I have a Seagate Barracuda 20GB, which I get 28.2MB/s (outer recording zone) under MS Windows 2000, yet 15.3MB/s under linux. That's almost half!!
I was getting 20.2MB/s with my older Maxtor 5120+ 10GB drive, but I can't understand why performance is less - although it was a older kernel(!). I get a nice 128MB/s buffer cache read speed though.
Indeed, I posted a question on these lines, but go no replies. It's a pity, since that extra speed would be 'free', and satisfy lots of linux (IDE) speed-merchants.
Dan __________________________ Daniel J Blueman Undergraduate - BSc Computing Science UMIST university - Manchester Direct line: 0161 933 3569 Mobile: 07775 583766 Email: daniel.j.blueman@stud.umist.ac.uk SMS: daniel.j.blueman@sms.genie.co.uk
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