I.nfraR.ed - KT7A @ 176.8MHz - 176.76 MHz Reference Clock

[ludek]

Very nice ! Is that limit of the chipset? In other words: what possibly limited you?

[I.nfraR.ed]

Yes, chipset limit. No difference between 3-3-3 and 2-2-2. Or possibly some of the buses/controllers, since nothing is locked.

You can see I've benched maxmem with tight timings at almost the same freq.

[ludek]

You can play around with TEC on NB or even better cooling. I had once ABIT KT7 or KT7a but was not working, blowen caps and something else, gone to gold-diggers... If you are interested in this I had once also a good-looking KT133 (a?) motherboard DFI AK74 (the name lol). It was back in the non-OC days so I don't remember exacly if had good clockgen. Maybe some SOLTEKs would beat this score. Keep pushing

 

 

EDIT

Hmm seems like that DFI AK74 has ICS 94215 and max 133 FSB, but I am not 100'% shure.

Edited October 1, 2015 by ludek

[I.nfraR.ed]

I tried chiller on NB - did not help at all. Volts helped a little.

This is with 4.4V I/O.

Maybe it's the mem controller, but there's no lower divider - only 1:1 and FSB + 33MHz. Second one not available at high FSB though.

Theoretical maximum for this board is 183MHz.

This was the first time I play with KT133(A).

[gradus]

4.4v its 3.3v line from PSU? What PSU is it?

[I.nfraR.ed]

I/O source is from 5V line (stock board allows up to 3.9V from bios), so I did a simple FB mod.

My 3.3V-modded PSU is Fortron 400 PNF and can go higher than 4V, but for this sub I used Seasonic 1000W Platinum.

[ludek]

Theoretical maximum for this board is 183MHz.

This was the first time I play with KT133(A).

How do you know the theoretical limits? Is it determined by clock generator or what?

 

 

This is with 4.4V I/O..

This is nice idea. Yesterday i was OCing old ABIT KG7 and there was I/O voltage settings in BIOS. Rising it a bit was giving me a better scores. (Nothing new )

 

And just to confirm this i can say that the same happening on Pentium 3 platform. Rising I/O is good, so good idea with this.

 

Maybe it's the mem controller, but there's no lower divider - only 1:1 and FSB + 33MHz. Second one not available at high FSB though.

I am still wondering what is all about this FSB+33 MHz "divider". On a number of motherboards I have seen the same option but was called "FSB+PCI". So if you start with 100MHz fsb +33 mem its 133 mem. But what if you do eg. 120 FSB?? Is it 153 or is it 120*1.3333(3)=160

Edited October 1, 2015 by ludek

[I.nfraR.ed]

Yes, it is FSB + PCI. With that "divider" it reaches roughly the same RAM frequency, but on lower FSB.

I have some Qimondas laying around and can try if it could go higher, but I think chipset/pci/agp is not able to go higher.

First thing I tried was to use the modded PSU with higher 3.3V line, but it did not help.

With the FSB + PCI option I could only boot at about 122MHz FSB and it stops at about 133 within windows.

Which is the same SDRAM freq I could reach with 1:1, ~133*1.33

Of course performance at 1:1 is better on these platforms.

At 133MHz FSB PCI/AGP should reset back to normal, but the "extra 33MHz" options is only available up to 122 in bios, then disappears.

Also bios has frequency addition (up to +28). Maximum you can set is 155 + 28 = 183MHz.

Edited October 2, 2015 by I.nfraR.ed