XFXREV2. 5770 3/2 OC! 240MH/s at $99

[Man From The Future]

Using Saphire Trixx oldest version available on their site, and afterburner,
set Voltage to: 1.25V in Trixx

Memory clock 300, in afterburner

Core clock 1085. (ab)

Is this the best possible MH/s/$?

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[kr105]

And how much mhash/watt?

[Jack of Diamonds]

Unstable overclock and massive overvolt.
The VRM will fry within 2 months or less since it already runs at 135c (275 fahrenheit) at 1.0880 voltage. You are destroying it running the core near 1.1ghz, unless you live in a freezer.

I prefer conserving the cards for resale value and future usage for a sacrifice of 20-30mhash/s.

[Man From The Future]

Mine runs at 78C, it's called using a huge fan of doom that sounds like a jet engine

I'm afraid I don't know MHash/watt, I'll check once I can be bothered..., don't have anything to measure it with, and don't want to mess with 240V myself.

edit: howishot measure VRM temperature?

[Jack of Diamonds]

78C is just the core temp of the chip. It doesn't indicate stability. See the exploding gtx 590 on youtube.

Only way to measure the VRM is with a physical heatgun. (Or if there is a program I can't remember the name).

At default voltage I measured ~125-135 celsius on a 5770 and 5830 while mining.

[Man From The Future]

Which chip on the board is the VRM, I can just add a small heatsink, I have a bunch of them lying around

[LegitBit]

I run a 5770 at 1030Mhz without voltage tweaking plenty stable... though I do have a MSI Hawk edition with better VRMs and a nicer cooler.

Which chip on the board is the VRM, I can just add a small heatsink, I have a bunch of them lying around

VRMs are not chips.. at least not entirely (there is a chip that monitors/controls them).. they are capacitors, you could target a fan on them, but putting a heatsink on them wold be dangerous if the caps bust.
The capacitors have a scored surface to control explosion when they fail.

[LegitBit]

Also, 78C is awful. Likely the shaders are at 84C.

Max for many of these chips are 90-100C, but you don't want to be even close to that. 50-65C is where I like to keep mine, even when overclocked.

Use HWINFO to check more than just core temp.

http://www.hwinfo.com/download32.html

Run this in sensor mode.

[Man From The Future]

I'm afraid XFX5770s even at stock and 100% fan don't go lower than 66C in afterburner at full load for me... ;S

78C was wrong, from memory. 71C. Also, this the Afterburner temps, and ATi CCC reads 66C, however, I'll go with the higher ones from afterburner as worst case..

The I have a large fan covering everything on the closest-to-front 2/3s of the graphics card, too

Why do the capacitors reach so high a temperature, are they rapidly charging and discharging for voltage regulating purposes? ("switching"?)

If they're capacitors, why can't I just go and buy some equivelant, higher-maximum voltage high quality ones, de-solder the old ones, and put on the newer ones?

[LegitBit]

The capacitors are charged all the time.

The more voltage to condition, the more heat is generated. This is because a capacitor is meant to smooth out a signal by storing (buffering) or 'slowing down' an electrical signal.

In the process of storing electricity, resistance (think friction) is made in the capacitor, just as with friction, resistance generates heat.


I would recommend not messing with the capacitors, as they are spec-ed to condition the power in a specific way, replacing them would likely either cause irreversible undervolting/overvolting damage.

[Man From The Future]

Ah, PWM I guess anything more expensive would be stupid with this...

On the subject of changing the capacitors, as long as I keep the same uf, it should continue to work in the same manner...? :S

Sorry, a bit rusty on electronics, haven't done much in a year, been too busy with other stuff. (Anyoone else here use PIC32 microcontrollers? )