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IDE Bus Mastering?

S

SkuLLy|RT

Limp Gawd
Joined
Apr 16, 2002
Messages
499
Just a quick question.

Was just playing around on a new system I'm building and noticed a BIOS option to enable IDE Bus Mastering. Can honestly say I've never paid this much attention on any of my other systems, but would enabling it yield any sort of performance increase, or should it just be left disabled?

Thanks much. :)
 
Turn it off and you'll run in PIO mode, maxing out at 16MB/s per channel and using immense amounts of processor time.
 
shouldnt that be will dont? :p

leave Busmastering enabled
 
Actually, in rereading the first post, why is it disabled by default? Is this yet another pathetic effort by board manufacturers to reduce support calls by dropping everything into compatibility modes?

Ice, check you emails, man. I'm getting sick of PIO mode myself.
 
haha omy, now i'm not sure what's going on at all. :)

the board in question is an IC7-MAX3, and yes, the busmastering was disabled after resetting the BIOS.

was in there disabling some of the onboard features i don't need (like the serial ata raid, ieee1394) and just saw ide busmastering and thought to myself "hey, i have no idea what the hell that is, lets ask the [H]gods if its good or not". :)

edit:: so wait, is that a yay or a nay to having the busmastering setting in the BIOS enabled? :)
 
SkuLLy|RT said:
edit:: so wait, is that a yay or a nay to having the busmastering setting in the BIOS enabled? :)
Click to expand...

busmastering=enabled :cool:
 
There are two situations where you'd want to run in PIO mode: 1) the device doesn't support DMA 2) the controller, cables, or device are flaky or are fighting, leading to errors while in DMA mode. Your OS will detect this and adjust automatically if it was made since 2000.
 
there is potentially another explaination for that BIOS option
(BIOS vary alot, and how mobo manufacturers lable stuff as well though there are only 3 main BIOS manufacturers Award, AMI & Phoenix, the customize the BIOS for the manufacturers)

It might relate to the SATA and IDE Busmastering (Enabling both channels on a mobo and controlling how the Boot Order Scan works)

I always carefully review each mobo manual (if I can download it before I buy)
for what a particular BIOS offers

can you list the reference in the manual?


Sorry Snugglebear, Ive been integrating a new computer for my Brother and before that disinfecting a computer for a freind, so I hadent checked my email in a few days, had that box offline, Active SMART impressed me, but its in the paid category
 
this thing is kicking my ass now. with the IDE BUS MASTERING option in my IC7's BIOS ENABLED, my new rig is actually feeling a tad bit sluggish to be honest. went back into the BIOS and loaded the OPTIMIZED DEFAULTS just to make sure i wasn't seeing things wrong, and low and behold, IDE BUS MASTERING is DISABLED by default.

can you list the reference in the manual?
Click to expand...

went ahead and grabbed the pdf from the Abit website, Ice Czar, and found something interesting. under ONBOARD IDE DEVICES, instead of it saying IDE BUS MASTERING like it does in my BIOS, the manual says IDE HDD BLOCK MODE (page 52 of 94 from the Abit IC7 pdf manual).

IDE HDD BLOCK MODE - Enable/Disable - This item determines the use of block mode for IDE HDD
Click to expand...

that's what comes straight from the Abit pdf manual, which is not what i'm seeing in my actual BIOS.

for the moment, installs seem to be going quite a bit quicker with IDE BUS MASTERING DISABLED in the BIOS, so i'm going to leave it like that for a bit. is there any software i can grab to see what modes my HDD and DVDRW are running in, or is there anyway i can find this by looking around XP?

much thanks for your input everyone. :)
 
Block mode is different from bus mastering. And most recent motherboards I have seen (mostly nForce2 boards) have bus mastering disabled by default. I don't believe that doing so drops you to PIO mode, but I guess it's possible. I don't feel like testing it.
 
dandragonrage said:
Block mode is different from bus mastering. And most recent motherboards I have seen (mostly nForce2 boards) have bus mastering disabled by default. I don't believe that doing so drops you to PIO mode, but I guess it's possible. I don't feel like testing it.
Click to expand...

well i'm game for testing, just tell me what you would have used. :)
 
i'll be damned, i've got a MAX3, lemme help you out by turning that on too. =)

flip

edit: everything seems fine to me..?
 
fLiPaChu said:
i'll be damned, i've got a MAX3, lemme help you out by turning that on too. =)

flip

edit: everything seems fine to me..?
Click to expand...

notice any performance differences?
 
I'm back, and still fairly confused. :)

Spent the past two or so hours defragging, rebooting, running ZDMARK and HDTACH, changing IDE BUS MASTERING on and off.. really good times. :p

First observation - With IDE BUS MASTERING on, and even with it off, XP always set my HD to UDMA Mode 5, and always set my DVDRW to UDAMA Mode 2. So even with IDE BUS MASTERING disabled in my BIOS, I was never dropped to PIO Mode.

Second observation - With IDE BUS MASTERING on, my CPU usage is through the roof when installing games and moving files. When running ZDMARK Disk Inspection tests, CPU usage was clocked @ 11.4% with BUS MASTERING ENABLED, vs 4.74% with it DISABLED. This was also reflected in HDTACH tests, 5%+-2% (ENABLED) vs 1%+-2% (DISABLED). SiSoft Sandra was throwing out numbers like that last night as well, but I uninstalled the software and disregarded the results thinking they were way off base (which apparently they weren't).

Third observation - Maybe my motherboard is assbackwards?

A non-number based observation that I've been making with BUS MASTERING ENABLED is that when moving large files (a couple hundred MB), my system often freezes for a moment of two, and the HD LED just lights up my case. This isn't the case with it DISABLED however :confused: . I'm looking around now to make sure I didn't miss any drivers when I installed this board. I know I got the most recent Intel INF updates, so if you know of anything else that I should have installed, feel free to lemme know. :D

(Also, this is the exact readout from ZDMARK, in case you wanted to see it)

- SkuLLy
 
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