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Old 08-11-2019, 09:41 AM   #27
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Join Date: May 2008
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Post BFG GeForce 7300 GT AGP [BFGR73512GT]

I’m back!
Been busy lately with my new job and also spending most of my free time building up computers with some of the junk I’ve accumulated through the years. But none of that has stopped me from still doing the occasional video card cooler mod.

For today’s post, I have a BGF GeForce 7300 GT, model BFGR73512GT. There’s nothing special about such an old card… except note that this is an AGP video card. I don’t expect most folks to be following up on “trends” with old “retro” PC hardware (I don’t really either), but the value of AGP video cards has steadily gone up in the last few years – especially the more powerful cards (and especially VooDoo cards, if you haven’t noticed. )

So, when I saw this card on eBay for $10 (including shipping), I couldn’t help but snatch it up. This is what I ended up getting:

Now, does anyone remember that GeForce 8400 GS PCI card I showed on the last page? If yes, do you see resemblance anywhere? I’ll give you a hint: look in the center of the card.
- The above 7300 GT uses the same crappy cooler as that 8400 GS card with a tiny 40 mm screamer fan. At least the fan wasn’t seized this time, though. In any case, the cooler on this BFG 7300 GT wasn’t adequate to keep the card cool at normal room temperatures, just like the 8400 GS. And here is proof of that:

At 20C (68F) room, the GPU core temperature under full load hit 57C and would have kept going up if I didn’t stop the testing. The 8400 GS did much worse, of course, because it has a higher TDP, IIRC (maybe 5-10 Watts more.)

On that note, I’d guesstimate the G73 core is probably rated for about 25-40W, depending on clock speed (maybe closer to 25-30W for the 7300 GT). The G98 of the 8400 GS is probably at least 30W. Whatever the case, that small finless U-shaped “aluminum bracket” cooler above is certainly not adequate for either card. And you know what this means here: it’s cooler modding time!

Step 1: remove the old cooler and clean the GPU core.

Closer look of the G73 core:
It’s a pretty small die, so be careful if doing your own home-brew coolers. It’s not hard to crack these at all.

Step 2: make/put on a new heatsink/cooler.
You might be thinking this is going to be yet another cut-up, Frankenstein-ed Xbox 360 heatsink… but, nope! Instead, I decided to try something different and re-used the stock heatsink that came with this XFX GeForce 8600 GT video card that I recapped last year (complete post here.) I figured the TDP of the 7300 GT GPU should be low enough for the stock 8600 GT cooler to handle. After all, regular GeForce 8600 GT cards have a TDP of 44W, and the XFX version above is ~60W TDP with the factory OC. Thus, it *seemed* logical that the 8600 GT cooler should be able to handle at least 30W of TDP. Moreover, the cooler from the XFX 8600 GT also matched the stencil outline drawn on the 7300 PCB, as did its screw pattern. So this cooler seemed like a perfect fit every which way… well, almost:
I had to do a bit of cutting/drilling for the GPU’s crystal reference clock to fit. But other than that, it did fit well.

Up next, I put on a 50 mm fan that I had from another XFX 8600 GT (the first one that I recapped.) Of course, I knew this 50 mm fan would be very loud at 12V (and likely not last very long), so I attached a resistor in series with it. I don’t remember what resistance exactly, but I think 100 Ohms. All I remember is that the fan was running on ~6V. Here is the “new” cooler after these mods.

Step 3: Test your handiwork!
In terms of noise, this modded cooler was absolutely silent. Meanwhile, the cooling did improve a bit, but not as much as I would have liked to see. Temperature graphs:

The maximum GPU core temperature peaked around 50-52C after a long session of testing (30 minutes or so) with the same room temperature. Compare that to 57C with the original cooler, and this was with only a few minutes of loading. More than likely, that stock cooler would have gone a bit over 60C if kept at 100% load long enough. Thus, this mod not only lowered GPU temperature by 5C minimum, but the 50 mm fan running at 6V made the card pretty much silent.

Of course, it should be noted here that 20C / 68F is a fairly cool room temperature (at least for my twig structure .) “Normal” room temperature (at least according to most science and physics books even today) is considered to be 25C (77F) and it’s what most hardware is rated for anyways.

Since temperature of the cooler rises proportionately with the room temperature – that is, for a set fan speed… at 25C, even my cooler mod above would make the GPU get a bit hot. That means, an increase in 5C of Ta will result in 5C rise for the GPU (i.e. I’d get around ~56C.) As a matter of fact, I let room temperature go as hot as 28-29C in the summer. So with that kind of temperature, I expected even my cooler mod would have a hard time keeping the GPU under the 60C mark. Thus, it seems like more work is needed on my moded cooler. The first thing I thought of was to put on a fan shroud, so that all of the air from the fan actually goes towards the heatsink and not elsewhere. If you remember from that 8600 GT thread above, this third card did not come with a fan shroud on the cooler. As such, I made my own. Using cardboard, I quickly put this together:

And here it is on the cooler:
Not very pretty, but it does the job.

This helped lower the temperature by 1-2C under load. However, I still wasn’t satisfied. So I removed the series resistor for the fan and instead hooked up the fan directly to 7V (by grounding the negative lead of the fan to the 5V rail.) I couldn’t find a convenient test point for the 5V rail, so instead I removed the entire fan connector and had it connect as follows:

Final look on the fan mod…

This yielded the following SpeedFan GPU temperatures:

… which were still not great, considering the GPU again reached close to 57-58C after a few minutes @ 100% load and would have likely gone over 60C if left running over 10-20 minutes. However, note here that the above tests were completed at 82F / ~27.7C room temperature, which is considerably hotter (about 7C) than before. With less demanding games that didn’t stress the GPU to its absolute maximum, I as getting closer to 52-53C on the core.

So overall, this cooler is a decent improvement over the stock one. Despite being used on the 8600 GT (a 47-60W TDP card), I still find it wasn't adequate for this ~30W TDP card. On the plus side, it still only takes a single slot (which is rather rare with my mods. ) And, I was finally able to reuse some of these stock cooler parts that otherwise keep accumulating in my junk boxes.

I just wish this card had implemented some form of fan control that would allow me to crank the fan under heavy load and then go back down to 6-7V in idle mode. Unfortunately, there is no missing or empty circuit on this card that I can fill in to enable this – original fan connector is simply hard-wired to 12V. I’m sure that 50 mm fan would improve the cooling quite a bit at 12V and likely keep the GPU under 60C with the abovementioned room temperature. But it would be loud (I actually tested it before) and it certainly won’t last as long.

Anyways, I’m not all that worried, though, as I still haven’t decided in what PC this card will go in. So with that said, this cooler mod should suffice for now. If I do any revisions on it, I’ll update this thread.
Attached Images
File Type: jpg BFG GeForce 7300 GT AGP [BFGR73512GT] (1).jpg (356.8 KB, 20 views)
File Type: jpg BFG GeForce 7300 GT AGP [BFGR73512GT] (2).jpg (345.6 KB, 19 views)
File Type: jpg BFG GeForce 7300 GT AGP [BFGR73512GT] (3).jpg (154.3 KB, 1 views)
File Type: png BFG GeForce 7300 GT - stock HS and TIM, 68F Ta room.PNG (12.2 KB, 19 views)
File Type: jpg BFG GeForce 7300 GT AGP [BFGR73512GT] (4).jpg (211.3 KB, 2 views)
File Type: jpg BFG GeForce 7300 GT AGP [BFGR73512GT] - GPU chip.jpg (63.0 KB, 2 views)
File Type: jpg BFG GeForce 7300 GT AGP [BFGR73512GT] - cooler mod v1 (4).jpg (82.8 KB, 4 views)
File Type: jpg BFG GeForce 7300 GT AGP [BFGR73512GT] - cooler mod v1 (1).jpg (163.7 KB, 4 views)
File Type: jpg BFG GeForce 7300 GT AGP [BFGR73512GT] - cooler mod v1 (2).jpg (67.5 KB, 4 views)
File Type: png BFG GeForce 7300 GT - 8600 GT HS & 50 mm fan @ 6V, Shin-Etsu TIM, 68F Ta room (2).PNG (11.3 KB, 18 views)
File Type: jpg BFG GeForce 7300 GT AGP [BFGR73512GT] - cooler mod v1 (6).JPG (46.0 KB, 19 views)
File Type: jpg BFG GeForce 7300 GT AGP [BFGR73512GT] - cooler mod v1 (5).jpg (154.8 KB, 3 views)
File Type: jpg BFG GeForce 7300 GT AGP [BFGR73512GT] - cooler mod v2 (2).jpg (172.2 KB, 18 views)
File Type: jpg BFG GeForce 7300 GT AGP [BFGR73512GT] - cooler mod v2 (1).jpg (132.8 KB, 18 views)
File Type: png BFG GeForce 7300 GT - 8600 GT HS & 50 mm fan @ 7V, Shin-Etsu TIM, 82F Ta room (1).PNG (11.8 KB, 18 views)

Last edited by momaka; 08-11-2019 at 10:32 AM..
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