4850,4870 or 9800GTX KO @ 1680x1050?

[slugg]

Originally posted by: AmberClad

Originally posted by: Sylvanas
There is some complex maths that goes into this (someone may be able to explain it better), but it is my understanding that if you have two devices outputting the same amount of sound (Db) it will NOT be twice as loud, in fact it will be only just above that of the sound of a single device. So really, two cards are not going to make a lot of noise, I experienced this with my 3850's in CF where two were no louder (to me) than one card in my case. :thumbsup:

Interesting, thanks for the info. Well, I guess there's also the option of getting a single 4850 now, and adding a second when that feels inadequate. Decisions, decisions...

This "complex maths" is awesome. I study the art of maths, actually. Allow me to explain.

*Ahem.*

Basically, our human ears don't perceive sound intensity in a linear fashion. If we have a noise, then we double that noise's energy, it is NOT twice as loud. Physically speaking, sure there's twice as much energy being converted into sound waves, but our ears don't tell our brains that we're detecting twice as much energy. Our ears detect sound intensities on a logarithmic scale, not a linear scale. What this means is that if we double the sound wave energy of something (say, a video card), we won't PERCEIVE it to be twice as loud.

For this reason, us humans came up with the decibel (dB) unit - a unit that describes a logarithmic ratio. In this context, we're applying it to sound intensity.

So let's say you have one video card. We can say that 1 video card is as loud as 1 video card. Easy enough.

Now let's say we have 2 of the same video cards. Two video cards now doubles the energy being converted to sound waves. By doubling the energy, this second card adds 3 dB (decibels) to your overall perceived sound intensity. Usually, this is just written as +3 dB. So in conclusion, 2 of the same video cards is as loud as 1 video card plus +3 dB.

So back to the 2 video cards versus 1's noise problem... A single 80 mm case fan is around +25 dB in a silent room. By adding a second (same model/fan noise) video card, you'll raise your overall perceived volume by about +3 dB. Obviously, the +3 dB is negligible compared to the rest of your computer.

This is all assuming perfect conditions (which doesn't happen in real life), but it gives you a really good idea.

Enjoy! :beer: :beer:

 

[Sylvanas]

Originally posted by: slugg

Originally posted by: AmberClad

Originally posted by: Sylvanas
There is some complex maths that goes into this (someone may be able to explain it better), but it is my understanding that if you have two devices outputting the same amount of sound (Db) it will NOT be twice as loud, in fact it will be only just above that of the sound of a single device. So really, two cards are not going to make a lot of noise, I experienced this with my 3850's in CF where two were no louder (to me) than one card in my case. :thumbsup:

Interesting, thanks for the info. Well, I guess there's also the option of getting a single 4850 now, and adding a second when that feels inadequate. Decisions, decisions...

This "complex maths" is awesome. I study the art of maths, actually. Allow me to explain.

*Ahem.*

Basically, our human ears don't perceive sound intensity in a linear fashion. If we have a noise, then we double that noise's energy, it is NOT twice as loud. Physically speaking, sure there's twice as much energy being converted into sound waves, but our ears don't tell our brains that we're detecting twice as much energy. Our ears detect sound intensities on a logarithmic scale, not a linear scale. What this means is that if we double the sound wave energy of something (say, a video card), we won't PERCEIVE it to be twice as loud.

For this reason, us humans came up with the decibel (dB) unit - a unit that describes a logarithmic ratio. In this context, we're applying it to sound intensity.

So let's say you have one video card. We can say that 1 video card is as loud as 1 video card. Easy enough.

Now let's say we have 2 of the same video cards. Two video cards now doubles the energy being converted to sound waves. By doubling the energy, this second card adds 3 dB (decibels) to your overall perceived sound intensity. Usually, this is just written as +3 dB. So in conclusion, 2 of the same video cards is as loud as 1 video card plus +3 dB.

So back to the 2 video cards versus 1's noise problem... A single 80 mm case fan is around +25 dB in a silent room. By adding a second (same model/fan noise) video card, you'll raise your overall perceived volume by about +3 dB. Obviously, the +3 dB is negligible compared to the rest of your computer.

This is all assuming perfect conditions (which doesn't happen in real life), but it gives you a really good idea.

Enjoy! :beer: :beer:

Awesome thanks for the explanation :beer:

 

[toslat]

Originally posted by: slugg
This "complex maths" is awesome. I study the art of maths, actually. Allow me to explain.

*Ahem.*

Basically, our human ears don't perceive sound intensity in a linear fashion. If we have a noise, then ...........;

sorry short of topic:
I do agree that two cards wont necessarily sound twice as loud (unless in resonance) but a few comments
- Your analysis above applies to sound intensity and not necessarily to loudness.
- Loudness is subjective (relative loudness less so) and depends non-linearly on several factors including (but not limited to) intensity, frequency, duration, and persistence.
- everything is further complicated by saturation of the auditory nerves
- it seems loudness depends on the integral of the intensity within the recent past.
- its generally believed that a 10 fold increase (10dB) in intensity is required to double the loudness (given same monotonic sound sources).

 

[tuteja1986]

Originally posted by: bryanW1995
the 4850 is already ~ 10% faster than 9800gtx, so it should be => 9800gtx KO. the 4870 is ~ 5% faster than gtx 260.

Where did you find the software Vgpu increase? I thought that you had to hard-mod a 4850 to increase the Vgpu.

Well , I think you should look at future :! crossfire 2x4850 would be great

http://www.firingsquad.com/har...performance/page14.asp

Half life 2 episode Two 2560x1600x32 8xAA/16xAF
4850CF :83.9 275%
9800GTX :30.4 100%

Oblivion HDR 2560x1600x32 8xAA/16xAF
4850CF :46.3 356%
9800GTX :13 100%

Company of heroes 1920x1200x32
4850CF :66.5 228%
9800GTX :29.1 100%

ET Quake War 2560x1600x32 8xAA/16xAF
4850CF :72.6 246%
9800GTX :29.5 100%

 

[Sentry2]

Originally posted by: AmberClad
I'm looking at the exact same upgrade path as the OP (the pretty long in the tooth 8800GTS 320MB). If the OP's is like me, he's willing to pay up to around $300 for a video card (close to the original price of the G80 320MB). There's nothing wrong with a 4850, and it'd be a big jump in performance...but why not get a 4870 instead, if that falls into the range of your allotted GPU budget? I'd also consider a pair of 4850s, but then you've got twice the fan noise to deal with, so that's something to consider.

The difference between 1 or 2 4850's fan noise is pratically nothing.

 

[LightningRider]

Fan noise doesn't bother me much, what would bother me about dual cards is the heat.