Bigger reward for fast blocks ???

[happypal]

I've been mining at Slush's Bitcoin Pooled Mining for a little while now. I mine casually on my home rig 24/7 at 300MH/s (1xAMD6950). I was surprised to notice that overall I am rewarded much bigger rewards for Blocks that are solved quickly (and I don't mean in a per time since, I mean absolute reward):
- I get about 0.025 Bitcoins for Blocks solved in 30 seconds
- I get about 0.02 Bitcoins per block solved in less than 5 minutes
- I get about 0.017 - 0.013 for blocks in the 20min to 1h range
- I get about 0.01 Bitcoins for the 2h upwards

I don't understand this reward distribution? Can anybody else? My guess is it is a side effect of miners trying to game the other "share-based" pools?

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[zamarok]

It's about share submission, not time. I don't know if Slush's pool has stats you can view, but if they do, look at your shares for each block and multiply it by how much Slush's Pool pays per share. You can read about it literally on the front page of Slush's Pool's website; he explains it quite well.

By the way, your 6950 can do at least 400 easily. Mine is at home doing 430 MHash/s right now.

[happypal]

Well... Isn't share submission somewhat related to time? My computer is running 24/7, so I don't see why I'd get less shares on longer blocks? The front page links to http://forum.bitcoin.org/?topic=1976.msg50002#msg50002, where Slush explains it is a score based system. Are you referring to another link?

I'd be interested in your 6950 configs. As I said, I'm a casual miner, and I mine on my primary rig, so I don't want to push the overdrive too hard (I'm F'ed if I burn it). I'm with -v -w 128. I have one of those new low cost single Bios Saphire 1GB 6950 cards, whose shaders can't be unlocked (at you flash with no safety net). I've pushed the OC up to 840Mhz, where I mine at 330MH/s, with the card @ 79°. Any way to get more bang out of it without pushing the clocks further?

[zamarok]

Well... Isn't share submission somewhat related to time? My computer is running 24/7, so I don't see why I'd get less shares on longer blocks? The front page links to http://forum.bitcoin.org/?topic=1976.msg50002#msg50002, where Slush explains it is a score based system. Are you referring to another link?

I'd be interested in your 6950 configs. As I said, I'm a casual miner, and I mine on my primary rig, so I don't want to push the overdrive too hard (I'm F'ed if I burn it). I'm with -v -w 128. I have one of those new low cost single Bios Saphire 1GB 6950 cards, whose shaders can't be unlocked (at you flash with no safety net). I've pushed the OC up to 840Mhz, where I mine at 330MH/s, with the card @ 79°. Any way to get more bang out of it without pushing the clocks further?

I was talking about http://mining.bitcoin.cz/ which is Slush's Pool's website. I don't 100% completely understand the math behind it myself, so I hope someone else replies to this thread and explains it in-depth.

My 6950 setup:

Core clock: 1,000 Mhz
VRAM clock: 400 Mhz
CCC OverDrive: +20%
Core voltage: 1260 mV (I'm still tweaking this because I think it can go lower)
Temperature: 70 C
Fan speed: 70~80% (depends on time of day; ambient temps are hotter mid-day)
Arguments: -v 2 -w 128

The card I have is a Sapphire 2GB reference card, which is basically a 6970 with some of its shaders locked. I patched my BIOS to unlock the shaders, so it's essentially an overclocked 6970. VRAM isn't really used in bitcoin mining, so underclocking VRAM makes your GPU require less voltage. This is also my gaming rig... all I have is a crappy backup laptop, so I'm screwed if this burns out too lol, but 70C is a fine temp. I highly recommend forming your own fanspeed curve based on GPU core temp. You can do this with Afterburner or Trixx easily, in the fan control settings. That way your fanspeed will be dynamically adjusted based on your GPU core temp.

Oh, and open your case and point a table fan at your card. Not directly at it, but at an angle. My fan is on 'low', angled to blow the heat from my GPU out the back of the case. Having my case closed up trapped all the heat inside... the extra fan allowed me to overclock a lot higher.

[happypal]

Thanks for the info, I'll try lowering my vram. What's "-v 2"?
EDIT:nevermind.

[Cluster2k]

How do people get their 6950s to go so fast?  I've got a PowerColor 1Gb 6950, 800Mhz stock running at 850, 1250Mhz RAM and 0% power control setting.  If I push it to 875 the PC locks up and reboots.

Temp is 65C and fan speed 56%.  Is it safe to push the power control setting up to 20?

I tried to unlock the shaders by ripping the BIOS, changing the 6950->6970 setting and uploading back again.  No dice.  Card requires the BIOS switch to be flicked before the PC will boot.

How much difference to power consumption does reducing the memory speed through reflashing the BIOS make?

[zamarok]

How do people get their 6950s to go so fast?  I've got a PowerColor 1Gb 6950, 800Mhz stock running at 850, 1250Mhz RAM and 0% power control setting.  If I push it to 875 the PC locks up and reboots.

Temp is 65C and fan speed 56%.  Is it safe to push the power control setting up to 20?

I tried to unlock the shaders by ripping the BIOS, changing the 6950->6970 setting and uploading back again.  No dice.  Card requires the BIOS switch to be flicked before the PC will boot.

How much difference to power consumption does reducing the memory speed through reflashing the BIOS make?

To push it further, you need to give it more power; turn up the voltage. Only touch the voltage if you know what you're doing. If you're new to overclocking, I recommend you do some research, and experiment on a less-expensive card. Your fanspeed should be based on a curve ideally, not a set value. If your temps are below 90C, you're safe.. but I wouldn't recommend running at that temp 24/7. I would shoot for 75C max as a safe 24/7 temp.

Only the 2GB cards can be flashed to a 6970 BIOS. That's why most people don't buy the slightly cheaper 1GB version. I'm actually using a 6950 BIOS that was patched to unlock the unused shaders... I'm not sure if the 1GB 6950 can use that one, but it's worth a look.

[Cluster2k]

To push it further, you need to give it more power; turn up the voltage. Only touch the voltage if you know what you're doing. If you're new to overclocking, I recommend you do some research, and experiment on a less-expensive card. Your fanspeed should be based on a curve ideally, not a set value. If your temps are below 90C, you're safe.. but I wouldn't recommend running at that temp 24/7. I would shoot for 75C max as a safe 24/7 temp.

Only the 2GB cards can be flashed to a 6970 BIOS. That's why most people don't buy the slightly cheaper 1GB version. I'm actually using a 6950 BIOS that was patched to unlock the unused shaders... I'm not sure if the 1GB 6950 can use that one, but it's worth a look.

I tried power control at 20 and changing to 875Mhz, but the ATI's software began throwing up errors that the card had stopped responding to commands.  I'll just have to leave it at 850.

Thanks for clearing up the 1Gb/2Gb 6950 card issue.  I was wondering why reflashing wasn't working even though I was following the instructions.  330Mhash/s isn't too bad for a budget card anyway.  I'll get something better next time.