(V1 – More pics and notes will be added as people ask questions)
Well, after some late nights, a lot of tinkering in the garage, and a lot of whitepaper searching I have finally succeeded in pushing my GTS 450 and GTX 550 project cards to their theoretical limit without H20 or LN2... I could go into great detail about how I thought I toasted the 450 in particular a few times trying to find the right points to jump from, but I have created some detailed pictures to save any future hardcore enthusiasts such pitfalls and hassles.
Before I go any further though, let me give the standard disclaimer:
THIS -WILL- VOID YOUR WARRANTY, IF YOU ARE NOT CAREFUL IN SETUP, APPLICATION, AND TUNING YOU -WILL- NUKE YOUR CARD AND POSSIBLY MORE; THESE MODS REQUIRE A FAIR AMOUNT OF ELECTRONICS KNOWLEDGE AND SOLDERING SKILLS. I TAKE NO RESPONSIBILITY IF YOU DECIDE TO TRY THIS YOURSELF. DON’T TAKE ANYTHING THAT I WRITE HERE AS GOSPEL, YOU DON’T KNOW ME… RESEARCH FOR YOURSELF AS WELL, MAYBE I’VE WRITTEN SOMETHING IN ERROR… THIS IS ON YOU IF YOU DECIDE TO GO FORWARD… Ok... So some of you are asking, what's a VMOD? Well in short it is a hardware modification that allows the user to tweak certain aspects of the card beyond the original defined limits of the manufacturer. Typically this involves soldering points on the board to either join pathways, increase/decrease voltage, or create a resistance point to manipulate voltage or logic while in transfer.
Quick Glossary:
VMEM = Memory Voltage - For the 450/550 cards the stock voltage is 1.56v, this mod allows for a theoretical 5v in it's current mode [Farthest I've been on air is 2.15v w/ heatsinks on the RAM]
VGPU = GPU (Graphics Processing Unit) Voltage - EVGA BIOS's max is 1.150v, edited BIOS's can go 1.212v, and this mod allows for a theoretical 1.6v [Farthest I've been on air is 1.26v and that's getting sketchy]
OCP = OverCurrent Protection - This circuit monitors voltage and resistance to ensure that temps do not become too high, this saves cards, but it begins to give a hassle at about ~1.138v after a short bit, and only becomes worse as you go higher
Variable Resistor/Potentiometer/Trimmer = (VR) Think of this as a knob for a faucet, it can allow or restrict the flow of electrons on a particular pathway (
http://en.wikipedia.org/wiki/Potentiometer)
Note: These will have three pins, do not fret, just make sure that one of your solder points to the VR is on the center pin, then the other one that you choose (left or right) in this case is your ‘on’ side… Turn the dial away from the soldered pin to reduce voltage, and turn the dial toward the soldered pin to increase it.
Required Items:
Soldering Iron - A 35w minimum with a fine tip
Thin Solder - I use silver solder myself, but any small rosin core will do
Small Gauge wiring - 26 gauge or higher I'd recommended
Variable Resistor/Potentiometer/Trimmers – 1x 50k and 1x 20k – I use linear trimmers but those can be dangerous, so if this is your first time I’d recommend the small blue 20 turn potentiometers (
http://www.solarbotics.com/assets/images/rt20k/rt20k_pl.jpg) Note: These will have three pins, do not fret, just make sure that one of your solder points to the VR is on the center pin, then the other one that you choose (left or right) in this case is your ‘on’ side… Turn the dial away from the soldered pin to reduce voltage, and turn the dial toward the soldered pin to increase it.
Nail Polish or Quick Dry Superglue - Small wires and small leads, when you set them it's best to stick them down, I use these two as they are non-conductive once they're dry and can be removed later if needed.
Hot Glue - To place your VR's and LP4 at the top or side of your cards board for voltage reading and real time voltage manipulation
LP4 (Molex) Female Connector - (
http://upload.wikimedia.org/wikipedia/commons/3/31/Molex_female_connector.jpg) This connector makes for a good point to path your voltage read points to for easy access.
Patience and Common Sense - Most important... This stuff takes time and practice, I'm still learning and screw things up... Also, unless you’re making LN2 runs your card can’t do 1.5v VGPU and 5v VMEM, don’t be foolish… Modding is like crack, it’s all fun until it’s all bad, so be thoughtful at each step...
Mod: Voltage Read Points - This is the most important mod you will do, we need to know what voltages we are pushing to the RAM and GPU; even if you're only doing the GPU mod you will need to do this as Precision, Afterburner, etc. only read from the BIOS and not from the actual sensor (i.e. I have my VGPU @ 1.26v and most softwares will just show whatever the default voltage is - don't trust software for this) – Refer to the attached pics, 450 card owners can follow either set of VMEM instructions, I just included the front side PCB option as that’s what I used.
Mod: VMEM - The 450/550 cards use an Anpec APW7165A Voltage Controller IC (
http://www.anpec.com.tw/ashx_prod_file.ashx?prod_id=347&file_path=20110426155913276.pdf&original_name=APW7165.pdf), to gain control of this controller we need to place a 20k variable resistor (VR) on the FB (Feedback Input) pin 6 of the controller and then place the other lead from the VR on to a ground, in this case pin 3 of the controller. Now before you go soldering though make sure you know where you want to place your VR, for me I place mine on the top as if you look at my machine you’ll see I have some holes, but others may find the side more useful… Decide your spot and gauge your wiring needs/distances, then cut your wires, solder them to the VR, then use a small dab of hot glue to keep the VR attached; once this is done then solder to your PCB… Once you solder those two points in I would also put a small dab of super glue or nail polish on the points and a bit on the wire to pin it to the PCB… You don’t want movement on the wires or they –will- come loose which sucks…
To use this mod – Be sure to have your VR dialed away from the soldered side pin of the potentiometer before turning your machine on (read potentiometer note under definition or required items) or you will potentially smoke your RAM… Once you’re sure that you’re ready go ahead and place the multimeter leads in the two LP4 holes that your VMEM voltage reads are pathed to; then turn the machine on and watch the multimeter, if anything higher than 1.6v comes up then turn your machine off immediately and check to make sure your VR is set correctly and try again… Anything over 2v (unless planned for ahead of time) is dangerous territory… So once you’re booted up and your voltages look good, you may begin to –slowly- turn the VR toward the soldered joint end of the VR and watch as the voltage on the RAM slowly increases… NVidia 450/550 Cards typically use Samsung K4G10325FE-HC05 and Hynix H5GQ1H24AFR-T0C RAM, both are rated for 1.6v, but can be increased so long as they’re sufficiently cooled; I’m using small thin heatsinks and push 2.15v, although I’m not going –any- higher, and my results may not be your results… Remember, it’s all good until it’s not, and you can do permanent damage, go slowly and don’t go past your comfort zone… I’d try going to 1.62v, then open Precision or whatever SW you’re using to OC and begin pressing your Mclk’s up a bit higher and see where they land… If you want more then go to 1.65v, etc… I can’t stress enough, be careful, and touch your RAM to check it’s temperature, if it’s getting hot then back off; even if it’s working, if it’s hot to the touch then it may not be working by next week… Always use common sense when modding…
Mod: OCP Defeat – The precursor to doing the VGPU mod is to do the OCP Defeat mod as extra voltage will mean nothing if the OCP is going nuts throttling it back… Same order of events for soldering take place as I’ve outlined in the VMEM mod, but in this case you’re going to use a 50k VR. Once this is placed and soldered in be sure that your VR is set open (read potentiometer note under definition or required items), once you’re sure you’re ready then turn the machine on and load into your OC software of choice; what I would do is increase your voltage up as far as you can and then increase your VGPU just up to the point where you begin to freeze up and such (you know that limit)… Go start Vantage or whatever benchmark tool you enjoy and then begin increasing the potentiometer, you will probably get some repeated crashes, but so long as they’re not temp related it’s ok; just increase the VR to half way or so and you’ll (more than likely) notice that you’re not crashing as much or possibly not at all… This is good, so we can now lead into…
Mod: VGPU – Before you do this, have you modded your BIOS already? If not then I personally recommend that you try this first as this will allow you to go to to 1.212v without having to get into this final step… Unless you’re good w/ the soldering iron this is where things can get tricky as you’ll be moving tiny surface mounts from one DIP to another (I could write an article as long as this one just on how to properly do this part alone), and even once you’re done unless your watercooled or LN2 bound you’ll probably only increase to about 1.25 or so at most… It’s not a huge jump over 1.212v from a speed standpoint, and you’ll be risking a lot less if you’re not comfortable with these tiny solder points coming up… Your call…
The 450/550 cards use ON Semiconductor NCP5395 Voltage/Timing controller (
http://www.onsemi.com/pub/Collateral/NCP5395-D.PDF). This controller is neat in that it uses eight VID registers to calculate it’s voltages… The method is pretty simple, use the PDF above and match the VID’s I have listed in the attached pics to find the voltage you wish to try… The practice of this can be a bit harder as the surface mounts are quite small, but if you’re embarking on this then I’m assuming you have prior experience with this type of soldering… Not much to say here other than be careful, and make sure you’re matching the registers correctly as it’s easy to read them backwards and end up with a different voltage then you anticipated (bad)… So, to test I would place your multimeter in the two LP4 holes that you ran your VGPU voltage registers to, write down what you expect your voltage to be and turn the machine on; if you see anything higher than the voltage you expected then turn the machine off immediately and check your work then try again once your error is found… Once you’re seeing the correct voltage and all is well, go into your OC software of choice and begin seeing what your new GPU Mhz. limits are… Common sense should tell you that you need to pay –very- close attention to your temperatures; more voltage equals exponentially higher amounts of heat… I’d recommend that you replace the stock TIM on the heatsink and ideally upgrade the heatsink all together before embarking on this journey, but again, up to you and results may vary… If you’re finding that at the higher voltages your machine is freezing up a lot then be sure to play with the OCP defeat a bit to ensure that it’s just not OCP trying to stop you, but if OCP is completely defeated and you’re still freezing up then you need to go back a step or two in your voltages (enjoy more soldering – told you this part sucks) and see how that goes… Not all GPU’s are created equal, and some may find that even with the OCP defeat that you cannot stay stable at 1.212v… Things happen, it’s not EVGA’s fault as the card works at stock clocks just fine, it’s how the cookie crunbles…
Well, this should be a good first draft of coverage; this will be a WIP as I’m sure there’s plenty I’m not thinking about, and I still would like to add more pics, but the most needed ones are here… Feel free to ask questions or give me any additions you would like to see… If you tried this and toasted your card let us know that too… I won’t take any blame, but I also am fairly versed in how to play ‘sudden death round’ and find alternate paths to get things running again (I’ll make a separate post showing what my 450 card looks like up close – it’s UGLY at this point, but it’s been through hell and back to get this info so hopefully yours doesn’t have to).
Enjoy!!
Note: My camera sucks for macro/up close shots, so I had to use stock photos and add in details; it's all the better as my cards are rosin caked at this point anyways...
post edited by blkhole - 2012/02/06 23:35:19