Old-school hardcore overclocking

Printable View

Show 100 post(s) from this thread on one page

10-19-2009, 12:30 PM
massman

Absolutely amazing!!
10-19-2009, 12:39 PM
Turrican

sick stuff there :D
10-19-2009, 03:05 PM
eligray

Solid: Ceramic caps have extremely low ESR, making them great for stuff like this... why replace them? Is there a better solid-state cap out there, or are you talking about the cylindrical ones?
10-19-2009, 08:26 PM
TiN_

s0lid

Thanks for reply :)

Please, do not confuse people. Ceramic capacitors - are small brick-type ones, most of them without legs, for mounting on PCB top layer. They hape excellent ESR, ESL and can work with high frequency, like 1-100 MHz range. They are just perfect for filtering and noise removal. But they all have small capacitor, most large (and expensive!) of them have 22-68uF. That's way too small for high-power apps with 500kHz-1MHz switching range. That's why you can find a lot of "usual" cylindrical caps in cans, with electrolyte. They offer good capacity - to thousands of uF, but with much higher ESR, ESL and worse temperature stability. Also can caps usually working good for low frequency, below MHz's, it's like to push huge tank to move. Once you get it moving, it's hard to stop. More frequency > more parasitic heating > less stable... So to lower ESR vendors install a lot of caps in parallel.

Little note: A lot of people saw "digital" VRMs, with only ceramic caps. That's because Volterra (vendor who invented this power units) use high frequency (1-2MHz) for switching, and thus their VRM can work without need of big capacitance for storing charge. Faster frequency - less component size, with same power rating. Remember old bulky 50/60Hz transformers for house mains? They are huge, even with power output only tens of watts. That's because of 50Hz. Increase clock to 5000Hz - and you get 100 times less space and weight for same power. But when you go with extreme overclock - low capacity makes thing bad, and advanced people, like Hipro5 always add solid polymer electrolyte caps to help VRM powering high-power load.

Ceramic caps are perfect for fast transients, big can caps are good for low speed filtering and energy storage. But when you use both - you get pros from each type, and lowering "bad capabilities" of can caps alone a bit.

I'm looking forward for your X48 VRM conversion :D
10-20-2009, 12:19 AM
HDCHOPPER

Tin EOF :worship::bows::banana3:

Crazy Great Old Skool Modding man :up: beats soldering crystals to OC :D
This thread is just tooo much fun :clap:
10-20-2009, 01:34 AM
TiN_

http://www.xdevs.com/images/chiller/7800gtx_1.jpg

Continue :D

Added extra wires to get less drop on Vgpu voltage under load. Also added FB line from near-GPU caps. Added some extra grounds.

Videocard review on current state. 7800GTX Radeon powa edition :D

http://www.xdevs.com/images/chiller/7800gtx_3.jpg
http://www.xdevs.com/images/chiller/7800gtx_2.jpg

By the way, this is the ONLY 7800 videocard with TWO PCI-Express power connectors :D
10-20-2009, 02:13 AM
s0lid

Quote:

Originally Posted by TiN_EOF

s0lid

Thanks for reply :)

Please, do not confuse people. Ceramic capacitors - are small brick-type ones, most of them without legs, for mounting on PCB top layer. They hape excellent ESR, ESL and can work with high frequency, like 1-100 MHz range. They are just perfect for filtering and noise removal. But they all have small capacitor, most large (and expensive!) of them have 22-68uF. That's way too small for high-power apps with 500kHz-1MHz switching range. That's why you can find a lot of "usual" cylindrical caps in cans, with electrolyte. They offer good capacity - to thousands of uF, but with much higher ESR, ESL and worse temperature stability. Also can caps usually working good for low frequency, below MHz's, it's like to push huge tank to move. Once you get it moving, it's hard to stop. More frequency > more parasitic heating > less stable... So to lower ESR vendors install a lot of caps in parallel.

Little note: A lot of people saw "digital" VRMs, with only ceramic caps. That's because Volterra (vendor who invented this power units) use high frequency (1-2MHz) for switching, and thus their VRM can work without need of big capacitance for storing charge. Faster frequency - less component size, with same power rating. Remember old bulky 50/60Hz transformers for house mains? They are huge, even with power output only tens of watts. That's because of 50Hz. Increase clock to 5000Hz - and you get 100 times less space and weight for same power. But when you go with extreme overclock - low capacity makes thing bad, and advanced people, like Hipro5 always add solid polymer electrolyte caps to help VRM powering high-power load.

Ceramic caps are perfect for fast transients, big can caps are good for low speed filtering and energy storage. But when you use both - you get pros from each type, and lowering "bad capabilities" of can caps alone a bit.

I'm looking forward for your X48 VRM conversion :D

Well that's something new i didn't know, thx for sharing this info! :up:

What comes to my X48 vrm conversion, need to find out way to get phase controller turn on with only ESP connector connected, but i think it's voltage is taken from 5V or 3.3V. So not a big deal actually =P
10-20-2009, 02:19 AM
TiN_

Which PWM controller do you have? You can start dedicated thread, i'll try to help.
10-20-2009, 02:25 AM
s0lid

ISL6336

http://www.xtremesystems.org/forums/...d.php?t=234215 here's the thread :)
10-20-2009, 04:23 AM
Tuvok-LuR-

you are mad and I like it!
10-21-2009, 04:45 AM
loopy83

Did you measure the ripple of your extra psu? How high is Vpp?

Did you add the extra psu to the stock psu of the 7800gtx or did you deactivate the stock one?

Awesome stuff there :)
10-21-2009, 05:19 AM
Kal-EL

First time this noobs seen anything like this. Far out man, very impressed by you're knowledge :up:
10-22-2009, 09:20 AM
TiN_

loopy83

Ripple is quite high, it's because of wired connection to board and 2phase design (7800GTX is quite power hungry chip)
I've used external VRM because native onboard one was fully damaged, VGPU convertor just burned PCB away 4 layers INSIDE, I've posted damaged pic earlier in this thread. So I decided not to mess up with native VRM, and hook up Radeon's power :-D

So, I finished my benches with this mad 7800GTX :-D.

With core voltage 1.8V and Vmem = 2.4V, GPU chilled out by A/C unit chiller (-12 to -20°C antifreeze liquid in WC loop), and QX9650 @ ~4.6GHz 1.65V chilled to I've got:

http://hwbot.org/img/silver-trophy-hw.png
3Dmark05 - 12625

http://hwbot.org/img/silver-trophy-hw.png
3Dmark06 - 7298

http://hwbot.org/img/bronze-trophy-hw.png
3Dmark03 - 28105

http://hwbot.org/img/medal-hw.png
Aquamark - 191744

#12 3Dmark2001 - 65449 - http://hwbot.org/result.do?resultId=912039

Quite nice as for me :D
10-22-2009, 09:28 AM
Foamy

Lol man
hey you think it would be possible to replace memchips? fill it up with 0.8ns memchips 7800GTX with 1GB :D
10-22-2009, 09:31 AM
TiN_

Of course replacing memchips is possible, if pattern on PCB suits chips ;)

I've added memory to 8800GS 384MB card not a long time ago.

http://www.xdevs.com/images/g92gs2.jpg
http://www.xdevs.com/images/g92gs3.jpg

But there was blocked memory channels inside GPU, so just GPU didn't detected added rams :D Still if replace GPU from 8800GT on it, it will work. Maybe, LOL.

0.8ns mems are in FBGA-136 rectangular package. 1.6ns on 7800GTX is FBGA-144. So no way. :)
10-22-2009, 10:02 AM
Foamy

Quote:

Originally Posted by TiN_EOF

Of course replacing memchips is possible, if pattern on PCB suits chips ;)

I've added memory to 8800GS 384MB card not a long time ago.

http://www.xdevs.com/images/g92gs2.jpg
http://www.xdevs.com/images/g92gs3.jpg

But there was blocked memory channels inside GPU, so just GPU didn't detected added rams :D Still if replace GPU from 8800GT on it, it will work. Maybe, LOL.

0.8ns mems are in FBGA-136 rectangular package. 1.6ns on 7800GTX is FBGA-144. So no way. :)

But, with same package and replacing the ones that are on it, it coudl work? :D
10-22-2009, 10:20 AM
TiN_

There is no 0.8ns or even 1.1ns mems in FBGA-144, afaik.
10-22-2009, 02:39 PM
GraduS

Quote:

core voltage 1.8V

go for 2v+) i bench 7800gtx @ 2.2v :up:
10-25-2009, 12:58 PM
TiN_

GraduS

Спасибо, я уже набенчился с 7800 :)

So, 7800GTX experiments ended, but look, we have new zombie for our crazy experiments :-D.

That dead 9800GX2..

Sees only 1 GPU and bridge chip, and unlucky, primary GPU isn't working.

Resoldered G92's GPU's on both half PCB's of card, and bridge too, but no success, final is the same.

What to do next?

YES, KILL working 9800GX2 for knowledge and new ideas :-D
That's joke...taking second working GX2 and disassembling it for parts. I tried to test "dead" halfs with alive ones.

Simple checks, tens of screw-descrew of PCB's , and gotcha - that freakin interconnection FCB (flexible curcuit boards) between two parts of GX2 is dead. Using good FCBs from alive card on dead GX brings life to that pieces of hardware.

Heated dead FCB's to some very good temps... No way, assembled card isn't working still.
But if second half is laying near connected, but not mounted on HSF - card works.

http://www.xdevs.com/rep/gx2_1.jpg

Now I need another dead 9800GX2 to replace FCB's and continue evil sciences :-D

Tried Quad, but forgot that XP not supports it :D

http://www.xdevs.com/rep/gx2_3.jpg

BTW, there is XBOX GPU heatsink on laying part of GX :D

And NVIDIA Bridge chip is fool, P5B deluxe mobo used for test have only 1 PCI-E x16 and second is PCI-E x4. But that chip gives x16 on all 4 GPU's. LOL.

http://www.xdevs.com/rep/gx2.png
10-26-2009, 12:55 AM
Turrican

again nice work :clap:
10-27-2009, 10:01 AM
Dezmen

Omg dudes you crazy
10-27-2009, 05:30 PM
V2-V3

Simply WOOT!!!!
10-27-2009, 05:58 PM
drizzt5

Crazy!!!! Nice job!
10-29-2009, 02:45 AM
TRG

Lots of respect, I'm really enjoying your writing and photos! Please keep more information coming, I'm hungry for it :)
10-30-2009, 11:13 AM
Angmaar

Wow, that's very Xtreme! :up:

Show 100 post(s) from this thread on one page