Modder of anything with a cord or batteries
Hi, Guys, new to this forum,but not voltmods.
As for your Vref inquiry : Vref is the reference voltage of the gpu (The voltage the gpu sees as a "1", anything below that is considered a "0") (correct me if i'm wrong, but that is the standard definition of VREF in a digital circuit; should apply to vid cards too)
I have a Sapphire 9800 with Hynix mem 2.8 nS.
I bought the card off ebay for $31 (US). Guy tried modding it for a mac and messed it up.
I also flashed it with a powercolor VBIOS
When I did the voltmods, I decided to use my own method. I have a set of 4 DIP switches that allows me to turn each mod on or off individually.(while running, too) I dont have a digital camera so no pics; sry.
My voltages
VGPU: 1.85v
VDD : 2.7V
VDDQ:2.6v
VREF: 1.42v
Clocks : 435/375*2 (stock cooling with vantec tornado zip-stripped to the card)
3dmark 03 6650+ (saw 6700 once) @ 1024x768 @ 430/370 video and CPU@3.8
"The last three voltages are stock" you might point out. I found no benefit to either raising or lowering VDD, VDDQ, VREF. I only use the VGPU mod.
Here are a couple pieces of info for y'all
VDD is the main voltage of the DDR memory (3.2v MAX with ramsinks)
VDDQ is the voltage for the memory input/output buffers (also 3.2v MAX with ramsinks)
Never go over 1.50v Vref, you'll cook your gpu
Max GPU voltages
Stock cooling 1.7v max
Air cooling 1.8v max
water cooling 1.9v max
Phase change/peltier /w waterblock 2.0v
When you raise the GPU voltage, it allows the GPU to write to the memory better, but hinders read operations (relaxed read-ready timings help) but you will lose a few mem clocks
When using 2.2nS ram on a 9800 non xT PCB (R350) the speed is limited (usually 380*2) by the tracings on the PCB itself, when you up the voltage you actually can lose some overclocking potential (a few MHz)
Thats why ati changed the reference board for R360 and XT
How do I know all this? Simple, I hold a degree in computer and electronics engineering technology.
If you have any questions you can e-mail me @
gregbrown8257475@hotmail.com
I don't mind making new e-friends.
My main rig:
ABIT AS8 uGuru MB w on the fly overclocking
LGA775 Prescott 2.8Ghz @ 3.8 air cooled
512 MB (Grrr) Kingston (yuk) ddr 400 (soon to be corsair dual channel 1GB)
Modded 9800
Sata HDD
Xconnect 500w P/S
Hope this was helpful.