BVision overclocking !?

[delshay]

i once read somewhere on a website that the PERMEDIA 2 chip has been overclocked @ 120MHZ..


my bvision is overclocked with a **new** osc from 14.3mhz to 15.2mhz..

overclocking via the tooltype should not give u lock-ups..
at lease not on my set-up..

i can type in anything i like..

ie..if i type in MELTDOWN=170 or even 200 3d software will just go slower..no lock-ups

the best result for my set-up is something between 98 & 110,but im not useing this at the moment as my bvision is overclock with a new osc..

[delshay]

@ PIRU


that explains why anything as high as 200 everything slows down..


but i do not get lock-ups..

[delshay]

@ FRAMIGA

i have the following on my BVISION..

1x socket ( for changeing osc )

4x thermaltake heatsink on BVISION ram..copper

the other chips including PERMEDIA 2 has standard heatsink..no fans..( A1200 in desktop case cooled by three main fans..

NOTE: you must cool the other chips as well..

**ALL** heatsink have a wire sent to earth..

this not only reduce noise when useing prelude sound card but also inproves image...

if you get GFX corruption ( when overclocking ) it may be down power..as my BVISION has no regulator & is powered direct from powersupply..


BVISION is 3.3v..& i think CVPPC will be the same..

[delshay]

@ Framiga

no i have a ANTEC TRUECONTROL..

BVISION & BLIZZPPC is powered direct from power supply..

this has lots of advantages..

1. reduced heat ( no regulators )

2. less load on the 5v rail..more power for other chips/devices..

3. BVISION & BLIZZPPC processors get cleaner & more stable power..


ie: during boot-up only 5v rail drifts from 5.05 to 5.03.

...3.3 & 12v rail no change..


if i reduce 3.3 voltage a get GFX curruption.& lock-up...


answers: only the BVISION regulator is totally removed..

         BLIZZPPC regulator is disabled..

         power goes direct to both cards..

   ----------------------------------------------------

 typeing this with two 67.66MHZ osc fitted to BLIZZPPC
 & one 15.2MHZ osc fitted to BVISION..

[delshay]

@AmigaMance

i had the same problem..


then i did this..



          *** DO NOT DO THIS TO YOUR CARD ***


i lifted up regulator on the BVISION & added a heatsink on the back of the regulator with thermal glue..

this improved things a little but not a lot..it seems when overclocking BVISION along with a overclocked BLIZZPPC you will get lock-ups..


i changed all this by removing the regulator on BVISION & disable regulator on BLIZZPPC..

if you get lock-ups/GFX corruption ( when overclocking ) its more likely a power problem..


the regulator only gives out something around 3.314 ( if i remember correctly )..


im typeing this with a ( overclocked a1200 )running with two 67.666mhz osc on BLIZZARD..BVISION also overclocked with 15.2 osc..



  ------------------------------------------------------


if you have 256MB of ram **do not** fit anything above 68.66MHZ osc with all precharge turn off in the boot menu on the BLIZZPPC..

[delshay]

Some of my posting in the past is incorrect, so I will delete and clear this mess up. Let's start.

Overclocking the Bvision ram has little impact, the real speed is from the "PCI bus". The danger here is the chipset will overheat when running near their top end speed. but works perfect if you have address the proper cooling requirements.

It seems I also may have made an error in the Permedia 2 cooling, but I can't change it. All three of my Bvision has thermal glue.

When testing at high speed, Permedia 2 with alloy heatsink with a fan, Permedia 2 was still very hot, but the heatsink was very cool to the touch, which suggest the Permedia 2 may need a copper shim, then a alloy heatsink added on top. I have no idea if this method will work or will solve the problem.

If Bvision locks-up when overclocking SGRAM, it may need a small bump in the voltage beyond 3.3v. via the regulator ( don't exceed 3.6v) there's nothing to gain beyond 3.6v & even 3.6v is not required.    ...3.4v - 3.45v should be enough.

How far you can overclock the standard SGRAM with a small voltage bump depends on what make SGRAM is fitted.  

Note: With a small voltage bump via regulator, SGRAM & Permedia 2 will benefit from this and will stop some unwanted lock-ups when overclocking.   ...Regulator is on the Bvision card.

ALL MODIFICATION(S) AT YOUR OWN RISK

[delshay]

There is always a risk whatever device is overclocked, but user(s) still do it. Even manufacture(s) are doing it.

Permedia 2 chip failed at 4.5v+, so the absolute limit is 4v, but I would not go anywhere near that voltage, my Bvision(s) are at 3.6v and is still working. But if something goes wrong, it's not a problem for me as I can fix the problem.

The real performance is in the bus speed & lowering the Latency in EDO memory.

When the bus speed exceeds 75Mhz you will be able to play most games with 800x600 screenmode, as the bus speed also overclocks the PCI bus.

When the bus speed exceeds 92Mhz you can play Freespace with 1024x768 screenmode

Lots of time was spent getting the 2x128MB ram working at this speed (75Mhz+) completely error free. This is where no other user will see very high performance from their card, as the Dram chips are very rare & was already limited when ordered a few years back.

Permedia 2 can operate on 66Mhz bus, but I think something under the Permedia 2 tracks needs to change, not sure but I think it's wired for 33Mhz bus.