7900GT VOLT MOD - 7900GT OVERCLOCK -7900GT CORE MEMROY

7900GT VOLT MOD - 7900GT OVERCLOCK -7900GT CORE MEMROY
Posted:2006-04-10 By hardware review Number of View:18790
7900GT VOLT MOD - 7900GT OVERCLOCK -7900GT CORE MEMROY By :hardware review Posted:2006-04-10 xtreview is your : Video card - cpu - memory - Hard drive - power supply unit source 7900gt volt mod I received my 7900GT yesterday, and could do quite some testing to solve some problems that where still there. The heaviest test I could use was "Comanche 4 Demo Benchmark Test", because with this Benchmark I got black screens long before other benchmarks like 3DMark05 were doing. Black screens are the prove that the Voltage Regulator, the ISL6568, doesn\'t "like"something. This something can be either some sort of voltage protectection, either undervoltage, overvoltage or too much ripple. It can also be overcurrent in some form. I could go to 710Mhz on the core with AtiTool without artefacts, but Comanche did not let me get passed the 545Mhz, and gave me black screens above. This was with 1.55Volt Vgpu. To make a long story short, it was not the overvoltage protection giving me problems, neither was it the overcurrent protection. It turned out to be that with the preset switching frequency, the convertor could not supply enough energy. This type of "bucket"convertor supplies a packet of energy with each bucket that is tranferred at a clock period. To get more energy, more buckets have to be transferred, and hence the swiching frequency has to go up. That is exactly what I did, and every benchmark can now run at 710 Mhz with a Vgpu of 1.55Volt. The picture below shows AtiTool, where you see that it is running for quite some time without artefacts at 710Mhz Core and 1800Mhz Mem. Temp does not exceed 62C with my ZalmanVF700. 7900gt volt mod All the necessary mods are combined in the next mail, because I did not manage to get everything in this mail! 7900gt volt mod Resistor "J" is a 5Kohm resistor, and causes the Core Voltage, Vgpu, to be 1.2Volt in the unmodified situation. Replacing this resistor with a 50Kohm resistor, changes the Vgpu to 1.5Volt. In the picture hereafter, you can add to this voltage, thus being 1.2 or 1.5Volt, another .05, .1 and .2, either as a single step or as a combined set of steps. So your options areNULL.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5 or 1.55Volt and with the 50Kohm modNULL.5, 1.55, 1,6, 1.65 and 1.7Volt as a maximum. Resistor "H" measures 3.5 Kohm, and controls the Over Current Protection. If you suspect the OCP giving you trouble, you can double this resistor to 6K8 Ohm. I had no problems, so you can probably leave it as it is. Resistors "I" are said in the previous thread to disable the Over Current protection . THIS IS NOT THE CASE. These resistors. measuring 1,8Kohm, are meant to balance the current between the two pair of switching Mosfets to carry an equal amount of load. Leave them, or replace them with values of 3,9 kohm which should only be done if you are having mysterious problems. And than comes a very important Mod, being resistor K. This resistor measures ca 80Kohm, and sets the switching frequency. Connecting a 100Kohm resistor in parallel, almost doubles the switching frequency, and solved my problems completely. You could eventually do this mod by pencil, try to get the value down to approx. 45Kohm. The next picture shows the Mods to change the 1.2 or 1.5 Volt to a higher value. C gives 0.05 Volt increase when shorted to ground B gives 0.1 Volt increase to ground and A gives 0.2 volt increase to ground, Plus any combination of A, B and C. 7900gt volt mod I have given two possible routes to achieve your Vgpu increase. Use either the upper or the lower set of traces. When you only use the red trace, you will have 0.05Volt increase. (1.25V or 1.55Volt) When you use Red plus Yellow, you will have a 0.15Volt increase (1.35Volt or 1.65Volt) When you use Red, Yellow plus Purple, you will have a 0.35Volt increase ( 1.55Volt, do not use it in combination with the 50Kohm resistor mod) Of course you can also connect a single point to get what you want, f.i. ground point C (sorry for the earlier typo) to get 1.4Volt. Although a bit more difficult to achieve, it is still doable. Go with conductive ink with a large U around all the other points towards ground. You can either do the modding with a thin wire and solder, or with conductive ink. Do not worry about all the points between C and B, they are not connected to anything, and are used to keep the lines as simple as possible. A bit messy, but here are the vmods i did 7900gt volt mod a quite good result for quite good d job 710Mhz Core and 1800Mhz Mem u can check here the 7900 gt super clock review or here for the 7900gtx super clocked review xtreview is your : Video card - cpu - memory - Hard drive - power supply unit source we would be happy to answer for your question . if you have suggestion or comment regarding this review our support would be glad to help just join our forum and ask u will get the best answer to discuss check our forum section :-) RATE THIS REVIEW 1 2 3 4 5    / 5   View Stat

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