What affect does memory timings have on FSB OCing potential?

[MichaelD]

It's a well-known fact that the KT133 chipset tops out at around 110MHz. I can't get get my mobo stable at anything more than a paltry 103MHz. I have all my memory timings maxed out. CAS2/4-way Interleave/Force 4-way interleave/etc. If I relaxed my memory timings, would that assist my FSB OCing attempts at all?

I'd much rather be at 10 x 110 than the 11 x 100 I'm at now. Thanks.

 

[Sleater]

Easing up on the agressive memory timings might allow you to increase your FSB above 103, but I'm not sure it's worth it.

The advantage of FSB overclocking over multiplier overclocking is the increased memory bandwidth you get with a higher FSB.

Before you relax the timings, have you tried increasing your v-core and/or vio for increased stability.

On my ASUS A7V (kt133 chipset) I've got 4-way interleave and CAs2 enabled on a 110mhz FSB. But to get stability I had to raise my v-core to 1.80 from 1.75. And the board sets the default +3.3 (vio) at 3.56 for extra RAM stability.

 

[Boonesmi]

it would depend....

if the ram is the limiting factor (meaning the ram isnt capable of running at those timeings with the fsb increased) then lowering the ram timings would help you increase the fsb


but.... if the ram isnt having problems running at those timings then it wont matter

are you running the ram at fsb speed, or fsb+pci? (meaning 100mhz or 133mhz?)
cause if the ram is set at 133mhz then its actually running at 103mhz +34mhz or 137mhz

 

[MichaelD]

Hi guys. Good questions. The ram is 512mb (256 x 2) of Crucial (Micron). My VCore is currently at 1.80. Anything lower (1.70/1.75) and it's not stable and freezes at the desktop. 1.80 is rock solid. Prime95 for 24 hours, while surfing, gaming, emailing, etc. The ram is running at FSB + PCI.

I have not tried raising the V I/O for fear of damaging my cards. The IO voltage also affects your PCI/AGP slots, right?

 

[Sleater]

The fact that ASUS set the default VIO on my board at 3.56 suggests its safe.

I can't imagine that raising it in the short term could hurt anything anyway.

 

[Boonesmi]

you could always try dropping the ram to 100mhz (just for testing purposes)
that way you could find the limit of the fsb (and know the ram wasnt the limiting factor)

but to really know the fsb limit you would also have to only use addin cards/hard drives that you know can take the increase in pci bus

 

[MichaelD]

Thanks guys. I think I will try upping the I/O voltage a bit. Have a good day.

 

[ErikS]

That's what I love about these boards, you read something & think "hey, why can't I do that?" - lol - I have to remind myself from time to time YMMV (your milage may vary). The best a KT133 board can generally do is 110mhz, my former board (Abit KT-7 Raid) wouldn't do more than 105 not matter what I did. Your Crucial RAM is very good & I'm sure it's not holding the board back so dropping the RAM timing won't do anything. Your only choice is to up the multiplier, if you flash with the newest BIOS your KT7-R can go as high as 14 (I think).

 

[MichaelD]

Hi Erik,

LOL! That YMMV is a b!tch! :Q I think you're right, but I'm going to try raising the voltage a tad...don't want to fry my GF3. I have tried an 11.5 multiplier with the full 1.85 volts and it locks at the desktop. A 12 mult and I have to reset the CMOS. I think the ceiling of my particular CPU is 1100....maybe 1150 with full voltage, but then it runs way hot.

I'm just trying to get some more mileage out of my KT133 board, which I love, before taking the $400 plunge for a KT266A/XP combo. I'm not really lacking CPU speed; 1.10GHz is not slow by any means. What I'm lacking is bandwith. Most folks are at 133; I'm still at 100FSB. Blahhh. I'm gonna build one killer rig come January.....sigh.