5750 slower than 4850?

iSpoody 1243

macrumors 6502
Original poster
Jun 29, 2008
435
1
Australia
correct me if I'm wrong but the 4850 has 800 pipelines and a 256 mb bus width as apposed to the 400 pipelines and 128 mb bus width in the 5750?
step backwards in terms of graphics?
 

TMRaven

macrumors 68020
Nov 5, 2009
2,099
1
correct me if I'm wrong but the 4850 has 800 pipelines and a 256 mb bus width as apposed to the 400 pipelines and 128 mb bus width in the 5750?
step backwards in terms of graphics?
5750 features GDDR5-- which, clock for clock, is roughly twice as fast as GDDR3. So in other words, the GDDR5 vram cancels out the 128bit bus (hypothetically)

There was also an article a couple months ago that said apple hogged up all the 5750s with 720 pipelines, hinting that they are using the desktop 5750s in the new iMacs. Rather it is underclocked or not is yet to be determined. If its is underclocked, expect performance to be around mobility 5850/5870. If it is default clocked, it will be-- well, a desktop 5750 :p
 

Hellhammer

Moderator emeritus
Dec 10, 2008
22,164
581
Finland
Depends on the clock speeds as it's likely underclocked desktop version. It's nice upgrade because of the VRAM but otherwise it ain't that huge upgrade
 

hcho3

macrumors 68030
May 13, 2010
2,783
0
Video ram has been upped from 512MB to 1GB. That alone is going to help your gaming performance for good.
 

TMRaven

macrumors 68020
Nov 5, 2009
2,099
1
Double the vram alone won't help most features in games all that much, it's all up to the memory bandwidth of the specific card, and 5750 is limited to 128bit bus. However, having a considerably larger vram buffer will help with things like higher textures--especially with the higher resolution the 27inch iMac has.
 

smelly cat

macrumors regular
Apr 17, 2010
132
54
i highly doubt that apple would replace the 4850 with a slower 5750. we won't know till we get our paws on some hard facts, but my guess is that the 5750 will be slightly faster.
 

Rodus

macrumors 6502a
Oct 25, 2008
679
0
Midlands, UK
^^ a few years back Apple replaced the Radeon x1600 with the HD2400, a slower card although technically capable of DX10 (which it ran very poorly). If the 5750 is a mobility version then it'll probably be slower, if it's the desktop then it will be a bit faster but hardly earth shatteringly so.
 

TheBearman

macrumors 6502
May 23, 2008
432
72
Cary, NC
Ok, let's say it is faster than the 4850 (by a fair amount). Since the video is a daughter card on the high-end 27 models do you think we'll see someone offering to sell or even exchange/upgrade the daughter card in the last gen iMacs?
 

prne10

macrumors member
Jul 27, 2010
40
0
I'm going to bet that the 5750 is between + and - 10% performance from the 4850. However, the 1GB of vram will be noticable on the 27" iMac. I really hope that this isn't a case of what they did a few years back when they downgraded just to run DX10.
 

Hellhammer

Moderator emeritus
Dec 10, 2008
22,164
581
Finland
Ok, let's say it is faster than the 4850 (by a fair amount). Since the video is a daughter card on the high-end 27 models do you think we'll see someone offering to sell or even exchange/upgrade the daughter card in the last gen iMacs?
Unlikely. Such upgrade would cost hundreds and the 5750 isn't that much faster. You're better off selling your current and buy a new one
 

dwarnecke11

macrumors 6502
Nov 29, 2009
354
0
The 5750 should run a bit cooler than the 4850. I really want to see some benchmarks. They're shipping today so it shouldn't be long.
 

Hellhammer

Moderator emeritus
Dec 10, 2008
22,164
581
Finland
The 5750 should run a bit cooler than the 4850. I really want to see some benchmarks. They're shipping today so it shouldn't be long.
If it's the desktop version which has NOT been underclocked, it will be hotter as 5750 has TDP of 86W while mobility 4850 has TDP of ~55W. If it's underclocked like most of us are expecting, then only Steve knows how hot it really is
 

Man-Droid

macrumors regular
Aug 27, 2009
187
0
Tampa, Fl
If it's the desktop version which has NOT been underclocked, it will be hotter as 5750 has TDP of 86W while mobility 4850 has TDP of ~55W. If it's underclocked like most of us are expecting, then only Steve knows how hot it really is
Curious, how do we know if we are getting an underclocked desktop 5750 or the mobile 5750?
 

Hellhammer

Moderator emeritus
Dec 10, 2008
22,164
581
Finland
Curious, how do we know if we are getting an underclocked desktop 5750 or the mobile 5750?
Mobility 5750 has 400 stream processors while desktop 5750 has 720. Someone just have to install Windows and download GPU-Z and it will show the accurate specs including clock speeds etc
 

Man-Droid

macrumors regular
Aug 27, 2009
187
0
Tampa, Fl
Mobility 5750 has 400 stream processors while desktop 5750 has 720. Someone just have to install Windows and download GPU-Z and it will show the accurate specs including clock speeds etc
Ah, thanks. Got it. Do the benchmarks usually reveal that information also?
 

prne10

macrumors member
Jul 27, 2010
40
0
Apple basically has always under-clocked GPUs on the iMacs/Notebooks. Oh, and ouch on only a 5750 for the 27" resolution.
As an AIO, iMacs can't cater to every demographic. The 5750 desktop, even when under-clocked, is enough for most consumers needs. Moderate to extreme gamers will be left in the dark, but did we ever expect anything else?
 

DesmoPilot

macrumors 65816
Feb 18, 2008
1,171
26
but did we ever expect anything else?
No, not from Apple; Just thought they would of opted for something with more to it than a 5750. Can't imagine how many threads we're going to get from people buying the 27" iMac going "omgz why cant steam gamez run on my iMac at 2560x1440 with everything set to high settinz!!"
 

MrDexx

macrumors member
Jun 19, 2010
34
1
As an AIO, iMacs can't cater to every demographic. The 5750 desktop, even when under-clocked, is enough for most consumers needs. Moderate to extreme gamers will be left in the dark, but did we ever expect anything else?
From the sounds of it...the new GPU would have to be underclocked otherwise the heat could damage the iMac?

How much difference would the underclocked GPU vs last gen's 4850 really make in gaming?
 

prne10

macrumors member
Jul 27, 2010
40
0
From the sounds of it...the new GPU would have to be underclocked otherwise the heat could damage the iMac?

How much difference would the underclocked GPU vs last gen's 4850 really make in gaming?
Thats the million dollar question, and we won't know until someone gets on in their hands and runs some benchmarks.
 

flopticalcube

macrumors G4
^^ a few years back Apple replaced the Radeon x1600 with the HD2400, a slower card although technically capable of DX10 (which it ran very poorly). If the 5750 is a mobility version then it'll probably be slower, if it's the desktop then it will be a bit faster but hardly earth shatteringly so.
The X1600 was replaced by both the HD2400 (which was slower) and the HD2600 (which was faster). Actually, the HD2400 also replaced the GMA950 in the edu model (the lowest end iMac in the white iMac era) so it could still be considered an upgrade in performance.
 

gibsonjv

macrumors newbie
Nov 10, 2009
19
0
Ohio
The one thing I always try to remember when evaluating new iMac hardware is Apple is only concerned with performance up to the point it does not violate a particular thermal envelope. Once the envelope is broken other components tend to have shorter lifespans. Which in turn increases the load on Apples support structure. Will the "high-end" offering on the latest iMac smash any records? No. Will it perform well for 97% of its' intended audience? Assuredly and it should do so for years to come.
 
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