sandy bridge with > 100 mhz bus?

[mikedev10]

why does this seem to be advised as such a no-no? i'm at 103 right now - is this really a big deal?

"BCLK Base Clock - This is strictly a NO, anyone using base clock overclocking could/will cause damange to CPU/Mainboard."

 

[Xorp]

Because that's how Sandy Bridge's architecture works.

 

[Mopetar]

I don't know how much damage it will cause, but my understanding is that it generally wasn't stable beyond 110 MHz if you could even get it that high.

Also, the ~3-8% gained from increasing the BCLK paled in comparison to being able to get over 4 GHz on air. If you want every last bit of performance out of your system you'll do it, but it's not going to give you as much. I haven't heard anything about it damaging your system though.

 

[Soleron]

The base clock now provides the clock for more components in the CPU/chipset system. Some of those are never meant to operate at any clock except the standard one.

 

[dorion]

The base clock now provides the clock for more components in the CPU/chipset system. Some of those are never meant to operate at any clock except the standard one.

This. I once put a 1mhz overclock on my PCI bus and it introduced corruption into my hard drive data, you can probably get away with a slight overclock, but the majority of devices running off the bus clock in Sandy Bridge are not designed to be run at a different speed.

 

[mikedev10]

how does that happen? haven't people been overclocking to irregular bclks now for a long time as well? hasn't that caused all the same components to work at even stranger frequencies? i'm wondering technically where and why this can result in lost data/physical damage? i'm at 103 now and i am assuming it's perfectly fine

 

[IntelUser2000]

how does that happen? haven't people been overclocking to irregular bclks now for a long time as well? hasn't that caused all the same components to work at even stranger frequencies? i'm wondering technically where and why this can result in lost data/physical damage? i'm at 103 now and i am assuming it's perfectly fine

That's because pre-Sandy Bridge chipsets didn't have the clock generator integrated into the chipset. So when you upped the bclk on pre-SNB processors, it left things like SATA/DMI/PCI Express/USB alone.

Now because they integrated it, you aren't just overclocking the chip, you really are overclocking everything in your system. Even your hard drives. USB drives, video cards, maybe even your mouse and keyboard(I don't know if that's true but for the sake of understanding).

You can wait for the Z68 which is rumored to have the clock generator external again.

 

[mikedev10]

wasn't that also true before the crazy speeds of 150 200 etc though? i thought the same thing was going on in like 202 and such. like 2/3 bus is what your agp would run at, so instead of 66.666 it would be 67.333 etc. i don't recall hearing any scary things back then.

 

[Plimogz]

you're not remembering correctly.

The ability to lock PCI/AGP frequency was a big deal when overclocking the FSB.

 

[ElFenix]

you're not remembering correctly.

The ability to lock PCI/AGP frequency was a big deal when overclocking the FSB.

the 440bx chipset had (undocumented) locks for the PCI at 100 mhz fsb but not for the agp, so agp ended up running overclocked. it didn't matter for most graphics cards, iirc.

had the chipset not had that pci lock, though, it wouldn't have been worth the data risk to overclock like that.

 

[mikedev10]

i just noticed my ddr3-1866 (pc14900) ram was running at ddr2-1600. once i changed that i DID have problems - windows boot but my keyboard wouldn't work to type my password in! at 102 bus now and it seems to be fine. what i am confused about is why my crysis benchmarks seem poor in comparison to an anandtech test rig.

http://forums.anandtech.com/showthread.php?t=2147868

 

[smakme7757]

I max out at 107.4, but you have to keep in mind it overlcocks EVERYTHING tied to the bus. It's just not worth it unless you're after a CPUZ screenshot and your trying for a frequency higher than your multiplier will allow.

 

[mikedev10]

i've got almost an extra 100 mhz from it, and my youtubes is so much MOAR FASTARS !!!1