Gigabyte P35 and DPC Problem (and possible solution).

PangingJr · Apr 30, 2008, 06:15 AM

you can read about this problem and others experience from these webpages... Gigabyte P35 motherboards and DPC - Gigabyte P35 motherboards and DPC

and here, Gigabyte GA-P35-DS4 motherboard with DPC spikes - http://forums.hexus.net/scan-care-he...pikes-rma.html

For P35-DS4 users, if you have this problem there is possible solution to fix the problem, for now,
which by obtaining a new version of BIOS file and try with it, the BIOS version "13B" seems to solve this problem.

you can obtain the version 13B BIOS from...

1) there is a link to download the BIOS file on the above pages
2) or try contacting the Gigabyte support team for it.

a few things you should know about the 13B BIOS, this is Beta BIOS (or even before beta),
and another thing is, when using this BIOS, i find that i cannot change the CPU core voltage,
though the setting still exist, Auto, Normal and all of manually enter values are there,
but the CPU's core voltage will remain at a constant and certain voltage. the core voltage given by the BIOS will be vary from CPU to CPU, this depends on your CPU and the core voltage given by the BIOS and this can also mean you won't be able to overclock your CPU that much higher, until a newer BIOS is available or the BIOS is final.

swimtech · Apr 30, 2008, 07:36 AM

Very thoughtful of you to post this - will run it on mine (EX38-DS4) and let you know if anything shows up. Deferred Procedure Calls, interesting...

**Vikingod** · Apr 30, 2008, 07:43 AM

Excellent post, as usual.

PangingJr · Apr 30, 2008, 11:37 AM

and on this (below) webpage, there is a user comment on his GA-P35C-DS3R, also says he just got an "F11f" BIOS from Gigabyte for the GA-P35C-DS3R and it cures the problem completely.

DPC Latency Survey - Sound On Sound Forum

swimtech · Apr 30, 2008, 11:43 AM

Well then, appears Gigabyte is at least aware of the "problem" and working to remedy it - good news.

PangingJr · Apr 30, 2008, 12:25 PM

PangingJr · May 23, 2008, 07:54 AM

As for anyone who uses an EX38-DS4, for your information, as of now, BIOS version " F4b " seems to fix the DPC latency issue,
however, it appeared to me that all this BETA BIOS only fixes the DPC latency spike issue in OS like Server 2008 SP1 and may be include XP,
but there are some DPC latency spikes ( no better than F3 final BIOS ) when i ran the DPC latency checker program in Vista,
and What could be the cause of this? I don't know.

here's the results...

the above one when the computer in idle states... and the below during some loads...

PangingJr · Jun 13, 2008, 01:43 PM

DPC issues still present in Gigabyte EP45 boards?
DPC issues still present in Gigabyte EP45 boards? - XtremeSystems Forums

PangingJr · Jun 18, 2008, 04:21 AM

P35-DS4 Rev.1.0 BIOS "F13E"

Vista SP1 32-bit and Vista SP1 x64....

- Q9300 2.4GHz-3.0GHz C1E, EIST, TM2 Enabled, Normal Vcore.
- 1x4GB DRR2 800MHz 4-4-4-10 @ 1.95V,
- 4 hard drives (using SATA port of Intel ICH9R, 3 in RAID0),
- 1 eSATA (ICH9R),
- 1 SATA DVD RW (ICH9R),
- PS/2 Wireless Keyboard and Mouse,
- 1 LAN, 3 USB ports in use. a card reader, a printer and a pen drive.
- 4 Case FANs plugged into the motherboard's 3-pin and 4-pin connectors,
- 2 Case FANs plugged into power supply,
- 1 HD 3650 800/1800 MHz, Onboard sound,
- GIGABYTE's SATA and IDE, Firewire and Printer ports are disabled in BIOS.
- OS Vista SP1... running Windows's Default services... planty of services and applications running in background.

i think this F13e BIOS (for P35-DS4) is still like an engineering BIOS yet,
however, all these seems to me that, this time Gigabyte has actually nailed the DPC issue down to the BIOS and fix it.

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PangingJr · Jun 30, 2008, 12:44 AM

words about DPC Latency issue in Gigabyte P35/X38's are spread all over the net and i have been hearing about it on some certain forums for quite a while now.
this issue is not only happen in Gigabyte P35/X38's boards, i think it's mostly a BIOS issue (and sometimes can be hardware device drivers) and it can happen to any boards/chipsets.

i just found that a P45-based Asus P5Q-D has this issue when the board's BIOS having a certain BIOS on it, and is kinda worse than i used to see before on my Gigabyte P35/X38's based board,
but, once i tried using another BIOS the issue has been improved.