JP1A1 & JP1B1 CPU Clk Options

= ecs / = p4vxasd2+
January 25, 2009 at 16:57:23
Specs: Microsoft Windows XP Home Edition, 2.66GHz / 1G MB pc 133
I just upgraded my CPU to a 2.66ghz Pent 4 533FSB. However it doesn't run very stable at 533fsb, so I had to drop back to 400fsb. This means that the CPU actually only runs at 2.0ghz. The change of FSB speed is performed using mobo strap(s) not bios. It appears that when you set mobo options JP1A1 & JP1B1 for 133mhz, the PCI bus is clocked at 44mhz and the AGP bus is clocked at 88mhz. There doesn't appear to be any lock options that I can use to independently keep the PCI and AGP frequencies at 33mhz and 66mhz respectively . However I read this explanation of the mobo options on another post. It said ( in ref to mobo P4VXASD2+):
"There are two jumpers one inch above the agp slot. The top jumper toggles 100/133 fsb, the bottom jumper toggles 100/133 sdram."

Does anyone know for sure if these options can be used independently as suggested in that post? If so (1)which option strap controls the PCI and AGP frequencies? (2)Which option arrangement would be provide best performance with this mobo?

See More: JP1A1 & JP1B1 CPU Clk Options

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January 25, 2009 at 19:13:16
There is no option to change the PCI/AGP, it's automatic.

For 133MHz:
JP1A1 = jumper cap on pins 2-3
JP1B1 = jumper cap on pins 1-2

For 100MHz:
JP1A1 = jumper cap on pins 1-2
JP1B1 = jumper cap on pins 2-3

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January 26, 2009 at 09:49:34
Thanks for your reply Jam.
From your reply I gather that these two jumpers must BOTH be set to either 100mhz or 133hz for my mobo to function properly. My BIOS is quite old, so I also wondered if maybe a later version of the BIOS provided any additional options that could be used to overcome the side effects of these hardware options. It doesn't make sense to even provide the frequency options since using the higher setting (133mhz) raises the PCI and AGP frequencies proportionally. Browsing the tech groups, I found recommendations that the PCI frequency, for example, should never be higher than 36mhz (for stability purposes). I wonder why the ECS site would even show compatible P4 FSB533 CPUs for my mobo, if there is no way to lock the PCI/AGP. It appears that it will very likely be unstable at FSB533, unless I can find some way to decrease/lock the PCI and AGP bus frequencies. I am running the CPU at 2.00ghz (20 x 100mhz)and everything appears stable, so it looks like I should have opted for a higher speed CPU with a FSB400 rating. Any comments welcome.

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January 26, 2009 at 11:44:04
Your board officially supports 533MHz FSB (@ 133MHz) so the PCI/AGP buses *should* be running at their defaults of 33/66MHz when the jumpers are changed. What makes you think they're running at 44/88MHz? Did you confirm that somehow?

Do you have the manual for your board? I had a look at it & didn't see anything that states JP1A1 is for the FSB & JP1B1 is for the memory. There's also an addendum for the jumper settings...the original manual was incorrect. The settings I posted above are from the addendum.

You should also identify your board appears there were several:

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January 26, 2009 at 16:59:26
I use the Sisystem Sandra Lite program to analyze my system. It shows me that with the CPU CLK frequency increased to 133 mhz (from 100 mhz) a proportional 33% increase occurs on all the buses i.e. the FSB (400->533), SDRAM (100->133), PCI (33->44), AGP (66->88) etc.

I have the original manual (came with the mobo) and the later addendum for a P4VXASD2+, Ver. 5, (which is the only "plus" version that the ECS site shows they ever manufactured). I looked on my mobo and it says that it is a P4VXASD2+, however it gives no version # anywhere on the board. SiSystem Sandra says it's a P4VXASD2+ Ver. 1 (which is nowhere to be found on the ECS site). Just today I got an e-mail reply from ECS (after sending them my mobo serial # etc.) saying that they matched the serial # to an ECS M922LU mobo. This latest revelation by ECS has me totally confused. I looked at the manual for the M922LU and it appears to be pretty well an identical unit (physically, at least). I just can't make sense of it. Kinda crazy or what??

Anyway, with regards to the two jumper options (identical in both the + & LU manuals) they make no mention of using them to independently manipulate FSB and SDRAM. The reference I mentioned was to a posting from another site. I tried all combination and my mobo will only boot if both jumpers are set to 100 or 133.

Another thing that is very confusing is the BIOS information on the ECS site. It shows two versions with the same release date (the FRY site shows two different dates - Ver. 030310 being the latest). However, on the ECS site (under a section on "cpu support and features" for the P4VXASd2+ it notes the (required/latest??) BIOS as being 20815. I cannot find any other reference to this BIOS on ECS or any other site.
I ordered a new BIOS chip several weeks ago with "the latest" BIOS version, but haven't received it yet. I'll have to see if there is any info/detail with it.
Thanks for your help.

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January 26, 2009 at 17:24:08
PCChips is certainly among the worst for documentaion. Actually, they simply suck.

Version 3.3 BIOS

Version 5.0 BIOS

I notice this on two bios updates:

"release note:1.Adjust timing for stability and compatibility."

Guess they just can't get it right?
I'm amazed that thing will boot with pci/agp busses that far out of spec.


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January 26, 2009 at 17:35:10
Why would you buy a BIOS chip for such an old board...especially when there's nothing wrong with your current one? How much did that cost you?

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January 27, 2009 at 05:34:52
I didn't want to take a chance on flashing the BIOS, since I have never done one before. I could be "dead in the water", if I messed up. Yes,it's an old board but the computer has been very stable and reliable, although with today's applications, it's become rather slow. I was going to buy a new laptop, but I decided to invest less than $100 (in used parts) at this time. An upgrade in RAM has increased it's performance considerably, so now if I could run my P4 2.66Ghz at FSB533 I think I would be happy with it for a few more years.

Update: I just found a site which explains how my ECS P4VXASD2+ (no ver.) mobo is really a PCChips M922LU Ver. 5. I'm guessing the only difference was the price tag!!

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January 27, 2009 at 06:55:41
"I could be "dead in the water", if I messed up"

Flashing the BIOS is a very simple procedure. I don't know why people are so scared of it? Personally, I don't like the idea of yanking out a BIOS chip & replacing

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January 27, 2009 at 11:44:38
You're right, Jam, the procedure is fairly simple, once you weed through the misinformation on the Internet and nail down the correct utility setup to run the flash procedure. Since I didn't receive my new BIOS chip today I decided to live dangerously and flash the existing chip with BIOS 030310 (the latest?), which should have included updates to "adjust timing for stability and compatibility". All went well, but there was no benefit reaped from the update. My computer still won't run stable at FSB533 and I don't see any additional options in the new BIOS to control the overrun on the PCI and AGP bus frequencies. I also noticed that the BIOS/DRIVER scanner that I use (BIOS_AGENT) still shows that my BIOS is out of date. Any other BIOS scanners that you can recommend to see what they say? I am now back to FSB400 and using the BIOS "Best Performance Values" and my system is rock-solid. I am still searching for a way to lock the PCI/AGP on 33/66 mhz.

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January 27, 2009 at 14:24:41
"once you weed through the misinformation on the Internet and nail down the correct utility setup to run the flash procedure"

What's to weed thru? If you have an ECS board so you should get the utility, BIOS file & instructions from the ECS site. If you have an ASUS board, get them from the ASUS site. Gigabyte board? Use the Gigabyte site...etc, etc, etc

I didn't think the BIOS update would do anything. I think you should stop relying on a software program (BIOS_AGENT) to tell you what's out of date or not. It's 2009, do you think the software knows that the final BIOS update for your board was in 2003? All it does is compare realizes that the BIOS is 6 yrs old & that's all it knows.

This statement written by Skip is very important: "I'm amazed that thing will boot with pci/agp busses that far out of spec." I agree 100%. Default for PCI/AGP is 33/66MHz, 37.5/75MHz is generally considered the safe max. Some devices will still function with the buses slightly higher than than that, but 44/88MHz is just too far out of whack. The sound would be crackling, video would be messed up & data would quickly corrupt on the HDD. Your board officially supports 533MHz FSB so that means when the jumpers are properly configured, the PCI/AGP will run at 33/66MHz. I think you're just the victim of crappy software.

Are you sure you have all the jumpers properly configured for the type of RAM you're using?

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January 28, 2009 at 05:22:32
Yes the memory options are okay,I'm running PC133 set for 3.3V with all of the bank jumpers left open. I have some DDR (266) ordered, but I would like to resolve the stability problem before I install it. I have run the MEMTEST86 for hours on the PC133 and no problems have shown up. My main focus with this mobo is to try to determine (1) if it really supports FSB533, or are the FSB specifications stated incorrectly, (2) if it does, then how do you deal with the fact that the PCI/AGP frequencies are increasing proportionally with the higher FSB speed setting. I am going to try to get ECS/PCChips to clarify this situation.
Thanks again to those who replied. Your input is greatly appreciated.

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