HD4850 Toxic has NO fan control

Sylph-DS · Post by **Sylph-DS** » Sat Oct 11, 2008 2:49 pm

Hello SPCR,

I'm not sure whether it's been posted here yet, but since I just found out too late today, I wanted to make sure it was.

Here's the deal.
http://www.techpowerup.com/reviews/Sapp ... ic/25.html

Sapphire has chosen to remove the temperature based fan control mechanism from their cooling solution. The fan will always run at the same speed, no matter if you run an idle system in Antarctica or under full load in the middle of the Saudi Desert. When asked, Sapphire replied that they "noticed that on many systems the problem is that the fan always starts and stops - at different temperatures. So we decided to always run at the same quiet fan speed".

This approach results in one of the noisiest cards under idle. When compared to the reference design HD 4850 the fan is 16.4 dbA noisier in idle - that's over 40x the sound pressure. Under load the margin gets smaller, yet the card cannot compare to the reference design when it comes to fan noise. However, the increased fan speed results in much lower temperatures and higher overclocking potential. Unfortunately power users won't be able to adjust the fan via any software. No matter what fan speed the card wants to run at the fan will always be around 1700 RPM.

I had personally planned to keep the stock cooler on it for the first 6 months or so, just in case of failure. But, I guess right now I have to either take my chances and get an aftermarket cooler, or stick with the noise for a while (it really is by far the noisiest part in my system, sounds a bit like a CD-drive at 30x or so)

Other than the noise, I wouldn't worry about temperatures, I haven't put it through any really severe testing, but it barely came above 50C in a quick game of CoD4 on high at 1280*1024.

It's a great card, it really is, I just don't understand why they messed with the fan control...

deruberhanyok · Post by **deruberhanyok** » Mon Oct 13, 2008 7:12 pm

I had one of these up until last week. The VF900 is basically running at about 1800rpm at all times. It's more annoying than anything else.

I started a discussion on Ars Technica about it:

http://episteme.arstechnica.com/eve/for ... 9003084931

Basically there's no way to alter the fan speed via software (Catalyst drivers or Rivatuner) or BIOS edit. When they connected the VF900 to the onboard 4-pin power plug the fourth pin - which I assume is the PWM one - isn't connected to anything, there's just power, ground and RPM sensing.

The only way I could think to control the fan speed would be to use a fanmate, however, Sapphire used a smaller, non-standard-size 3-pin power connector on the end of the fan's power cable. See the pictures on page 3 of that article to see what I'm talking about.

Presumably if you could get connectors of that size and mod a fanmate with them you could then control the fan's speed like a normal VF900.

Why they couldn't have just left the standard size 3-pin connector there I have no idea.

Incidentally I wound up getting a Palit Sonic 4850 which is far quieter and uses the 4-pin connector for variable fan speed. It also has a redesigned PCB (shorter by 2cm I believe) with a 3-phase power solution.

Tech Power Up's articles show a Palit 4850 near the top of their "loud" list but that's a typo in the charts, if you go back you'll see it's from the review of the Palit 4870 card (which has one of its fans run at full speed at all times).

Sylph-DS · Post by **Sylph-DS** » Tue Oct 14, 2008 2:44 am

The question on my mind is how far can I go without voiding warranty? I have the healthy habit of keeping my hardware as standard as possible for the first few months, just in case of failure.

If I could just get the fan on 7v or 5v when in idle (through a simple rewire) that would already be a massive improvement (I can deal with noise when I'm actually using the PC, but if it's on during the night I just can't handle it).

I've been doing a little more reading and I'm starting to think the video card may be causing a coil whine noise I've been hearing recently. I may end up returning it and picking up Palit's Sonic 4850, which does have a varied fan speed.

I've noticed it too. I think I'm going to see my options when it comes to trading it in. Right now I think I prefer having my old (passive) X1600XT even though it's horribly outdated.

Thanks for the response and the link to the topic.

deruberhanyok · Post by **deruberhanyok** » Tue Oct 14, 2008 10:23 am

Yeah... I'll know for sure about that coil whine or whatever it was once I get all of my replacement parts. It was happening even with an X1600 Pro, though, so I'm getting the PSU replaced. I actually heard a similar noise, a hum of sorts, coming from one of my hard drives when I connected it to another system, so now I'm wondering if maybe it was just amplifying the hard drive's regular operating noise (have since ordered a different drive to test).

I understand what you're saying about voiding the warranty. It seems to me that the safest route is something that will fit between the coupler from fan power cable to the cable coming from the video card PCB.

If you had connectors of that size you could set up wires with a resistor on the power line to drop the voltage to a constant level (I'm guessing about 9v would bring the noise down a large amount and still keep temps much lower than stock), and if you ever ran into a problem you could just remove that cable.

As for an automated adjustable fan speed, I don't think it's possible without getting a PWM fan that would fit (and proper size connector for the PCB end of the cable) and modding the card's VF900. Even then you might have to alter the BIOS, as, from what I saw when I dumped mine (with GPU-Z and viewed in RBE) it didn't look like any adjustable speed settings were already in there.

Kaleid · Post by **Kaleid** » Tue Oct 14, 2008 11:00 pm

I have the Toxic and simply changed the noisy Zalman cooler to a S1 + Scythe Slipstream 120mm 800rpm fan. I didn't even try out the Zalman VGA cooler since those easily get dusty very quickly and are not quiet enough even at 5v.

As for coil whine. Had that too, but turned out to be the fault of a faulty Zalman PSU which I have since replaced. The (faulty) PSU also started whining when harddrives were under load...

Sylph-DS · Post by **Sylph-DS** » Wed Oct 15, 2008 2:10 am

Hmm.. Well, my coil whining could be PSU related. I wasn't using the separate GFX card cables before I had the TOXIC, and on top of that the TOXIC probably takes about about as much power as the rest of my system when under load, so I can imagine the load causing some PSU stress. But then again, the whine didn't really seem to be related to GPU load. For example, it would be on just during browsing and then turn off momentarily when I clicked on something..

Eitherway, I've emailed the shop where I bought it and I can just trade it in. I already took the card out and stuck my old card back in.

Now I can restart the search for a new GPU. The Palit is interesting, but it's barely available where I live, so I think I'll look around for something else.

Kaleid · Post by **Kaleid** » Wed Oct 15, 2008 2:15 am

Sylph-DS
What you just wrote is very familiar to me. Many websites automatically started the whining from the GFX so I didn't even bother to read them while I had that problem.

I tried several other graphic cards (like a x300 and x1900xt) and that didn't solve the problem at all...

So it could very well be PSU related.