Looking to buy a new graphicss card.

Is there a significant difference in RAC between 4850's vs 4870's?

Looking to buy a new graphicss card.

Is there a significant difference in RAC between 4850's vs 4870's?

About 20 percent.

I can't answer your question directly as I don't have a 4850.
I can only compare 3870s and 4870s.
Currently my 4870's rac is ~63,000, my 3870s' are ~21,000.

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Cheers,

PeterV

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Cards that can process MW at the minute:

3850 - 668Mhz, 320cores, GDDR3 @ 828Mhz
3870 - 775Mhz, 320cores, GDDR3/4 @ 900/1125Mhz
3850X2 - 668Mhz, 640cores, GDDR3 @ 828Mhz
3870X2 - 775Mhz, 640cores, GDDR3/4 @ 900/1125Mhz

4770 - 750Mhz, 640cores, GDDR5 @ 800 Mhz
4830 - 575Mhz, 640cores, GDDR3/4 @ 900 Mhz
4850 - 625Mhz, 800cores, GDDR3/4 @ 993 Mhz
4870 - 750Mhz, 800cores, GDDR5 @ 900Mhz
4890 - 850-1000Mhz, 800cores, GDDR5 @ 975Mhz
4850X2 - 625Mhz, 1600cores, GDDR3 @ 993Mhz
4870X2 - 750Mhz, 1600cores, GDDR5 @ 900Mhz

In general, more cores are better. In terms of RAC, use the % difference in core Mhz as a rough estimate (as it's also based on your CPU too).

So 4850 to 4870 is 625Mhz to 750Mhz, or a 20% jump, as CP said.

(Since writing this list, I'm going to scrap my plans to get 3 3850X2 to fill some PCI slots and go for 2 4850X2 instead for the same price.)

So in terms of RAC, using the 3850 as a normalised value of 1:

3850 - 1
3870 - 1.16
3850X2 - 2
3870X2 - 2.32

4770 - 2.25
4830 - 1.72
4850 - 2.34
4870 - 2.81
4890 - 3.18 to 3.74
4850X2 - 4.68
4870X2 - 5.62

Formula = (cores / 320) * (1+((Mhz - 668)/668)

So a 4870X2 will get you roughly 5.62 times more RAC than a 3850.

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So in terms of RAC, using the 3850 as a normalised value of 1:

3850 - 1
3870 - 1.16
3850X2 - 2
3870X2 - 2.32

4770 - 2.25
4830 - 1.72
4850 - 2.34
4870 - 2.81
4890 - 3.18 to 3.74
4850X2 - 4.68
4870X2 - 5.62

Formula = (cores / 320) * (1+((Mhz - 668)/668)

One can optimize your formula a bit ;)
Formula = (cores / 320) * (clock speed in MHz)/670
or even: cores * (clock speed in MHz) / 214,400

Actually your values are quite close to the numbers I came up with and posted several times already ;)

When neglecting the 1-2 seconds CPU calculation for every WU (which is justified if you have two or more concurrent WUs running), one can break it down to the following performance relations (taking the HD3850 as base):
3850 : 3870 : 4830 : 4770 : 4850 : 4870 : 4890 : 4890 OC (1GHz, is realistic with a good card)
1 : 1.16 : 1.72 : 2.24 : 2.33 : 2.80 : 3.17 : 3.73
Of course the ratios only applies for stock clocks (670MHz for 3850, 775MHz for 3870, 575MHz for 4830, 625MHz for 4850, 750MHz for 4770 and 4870 and 850MHz for 4890 with the memory speed only a very minor factor). The performance generally scales linearly with GPU clock speed.

Practically, the HD4700/4800 series are even a bit faster compared to the HD3800 series than these numbers indicate.

That ist quite close to the numbers I came up with an posted several times already ;)

I remember you writing it CP, couldn't remember where but wanted to do it myself anyway. I developed a spreadsheet based on RAC per GPU cost for my future reference. Looks like above £150 the 4850X2 is the way to go :)

We seem to differ on 4830 RAC though. Mine does seem low, but comparing core speed vs no. of cores and everything else on Wikipedia puts the 4770 well above the 4830. Apart from 4830 being a RV770 and 4770 being a RV740...

Here's the cost/RAC spreadsheet, if anyone's interested. It's in GBP(£) with the lowest price for each card I could find. Number on left is the money you have to spend. So at £60, it makes sense to get a 3850. At £190, it makes sense to get 4850s or 4850X2s. It's all relative, based on your PSU requirements and available PCs.

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We seem to differ on 4830 RAC though. Mine does seem low, but comparing core speed vs no. of cores and everything else on Wikipedia puts the 4770 well above the 4830.

We both have a value of 1.72 for the 4830 and 2.24/2.25 for the 4770. My list has a different ordering of the GPUs, it is sorted by performance ;)

We seem to differ on 4830 RAC though. Mine does seem low, but comparing core speed vs no. of cores and everything else on Wikipedia puts the 4770 well above the 4830.

We both have a value of 1.72 for the 4830 and 2.24/2.25 for the 4770. My list has a different ordering of the GPUs, it is sorted by performance ;)

I can't read :) Just looked below each card at that number =P

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I have a Gainward 4870 1024Mo DDR5 O/C and I produce nearly 100.000 points every day at 65°C without noise !

Whats with a HD 4350 .. is it supported? And how fast would they be?

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Have a N.I.C.E. day!

I'm running HD3850's in two boxes right now, for an avg. of 20K WUPD.

At USD 59.99, or ~ GBP 37.00, this thing is a steal: http://www.newegg.com/Product/Product.aspx?Item=N82E16814102794

-jim

A 4350 will not work as it does not support double precision.

Right now it is 38xx, 4770 & 48xx only.

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I'm running HD3850's in two boxes right now, for an avg. of 20K WUPD.

At USD 59.99, or ~ GBP 37.00, this thing is a steal: http://www.newegg.com/Product/Product.aspx?Item=N82E16814102794

-jim

Annoyingly a new 3850 here Jim is 50GBP. We have to pay a slight premium on our electronics no matter what the exchange rate unfortunately.

My quandry initially was the number of GPUs vs PPD.

A 3850 would get 20k daily, for 50GBP.
So 6 of those = 300GBP, 120k PPD.

Now if you got a 4850X2 for 150GBP, it's 90k PPD (based on the 4.68 ratio below).
So 2 of those = 300GBP, 180k PPD, and only takes two PCI-E slots.

Obv the difference is that a 4850X2 requires 1 6-pin and 1 8-pin to power it from the PSU, whereas a 3850 doesn't require anything iirc.

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3850 requires 1 6 pin...as does a 4850, but more watts...found that out the hard way...smoked a 400w 25a single rail PSU this morning after installing the 4850 last night...

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Click to help Seti City.

A 4350 will not work as it does not support double precision.

Right now it is 38xx, 4770 & 48xx only.

RATS! 46XX can be had for less than $100 U.S. (sometimes a lot less). I did find a 4850 for about $110 U.S. Interestingly enough, neither of my favorite vendors even carry the 4770.

And nVidia cards that will run SETI quite nicely can be had for for less than $100

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A 4350 will not work as it does not support double precision.

Right now it is 38xx, 4770 & 48xx only.

RATS! 46XX can be had for less than $100 U.S. (sometimes a lot less). I did find a 4850 for about $110 U.S. Interestingly enough, neither of my favorite vendors even carry the 4770.

And nVidia cards that will run SETI quite nicely can be had for for less than $100

Newegg currently has a Sapphire 4870 512MB with an instant $10 savings and a $10 mail-in rebate. Normally $139, with both the instant savings and the mail-in rebate, it's only $119. And free shipping on it right now too. That's not much over $100.

Disclaimer: I have no financial interest in Newegg, I just ordered one this morning. ;)

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Calm Chaos Forum...Join Calm Chaos Now

Newegg currently has a Sapphire 4870 512MB with an instant $10 savings and a $10 mail-in rebate. Normally $139, with both the instant savings and the mail-in rebate, it's only $119. And free shipping on it right now too. That's not much over $100.

Disclaimer: I have no financial interest in Newegg, I just ordered one this morning. ;)

Huh. I subsequently noticed that Newegg also carries a Sapphire 4770 for $109 straight up, though they were out of stock when I looked. $119 is pretty good, too.

This is all moot while I remain unemployed, though that may change soon.

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One thing that might swing it to the 4770 - the power consumption is low enough to where I might not have to do anything crazy by way of a PSU upgrade.

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