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Speculation: How good will a gddr4 4850 perform?

Last response: in Graphics & Displays
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a b U Graphics card
November 9, 2008 11:01:43 AM

This page caught my attention. hmm how good will this card perform?
November 9, 2008 2:04:40 PM

Well, here we go:

Use this formula for memory access bandwidth/capability:
(ddr# - 1) x single channel clock = effective clock
(Bus bandwidth / 8) x effective clock in ghz = overall capability

4670 = 2 x 1000mhz = 2000mhz -> 2ghz
9600gso = 2 x 900mhz = 1800mhz -> 1.8ghz
4850 = 2 x 993mhz = 1986mhz -> 1.986ghz
4870 = 4 x 900mhz = 3600mhz -> 3.6ghz
gtx280 = 2 x 1107 = 2214mhz -> 2.214ghz

4670 = (128/8) x 2 = 32 gb/s
9600gso = (192/8) x 1.8 = 43.2 gb/s
4850 = (256/8) x 1.986 = 62 gb/s
4870 = (256/8) x 3.600 = 115.2 gb/s
gtx280 = (512/8) x 2.214 = 141.7 gb/s

According to that site, the ddr4 ram runs at 2200mhz effective.

4850 ddr4 = (256/8) x 2.2 = 70.4 gb/s
So that's 70.4 gb/s compared to 62 gb/s for the memory.
November 9, 2008 4:50:32 PM

no point. you won't see much improvement in games.
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a c 130 U Graphics card
November 9, 2008 7:24:16 PM

Looks like someone got left with some GDDR4 on th ebooks that needed shifting. GDDR4 wasnt that great a step. Didnt stay about long did it.
Mactronix
November 9, 2008 7:31:05 PM

Difference between GDDR3 and 4 is not noticeable, its pointless as customisbetter said. AKA it dosent matter, just make sure their isnt a price premium attached to it.
a b U Graphics card
November 10, 2008 1:31:59 PM

i dont know much about the latencies from gddr3 to gddr5, but i was hoping (actually praying lol) this will put it nearer to the 4870 (especially when overclocked) or at least 10% faster compared to a superclocked 4850 ddr3. guess it wont happen.

thanks dagger for ultimately crushing and stepping on my dream lol, just kidding, thanks for those computation btw.

im PSU limited (supposed to buy the corsair tx-series as replacement from my vx450, with the help from people from the psu section, thanks), and budget limited and considering theres a bunch of games coming out, my 4870 dream is slowly melting away.



a b U Graphics card
November 10, 2008 1:36:05 PM

mactronix said:
Looks like someone got left with some GDDR4 on th ebooks that needed shifting. GDDR4 wasnt that great a step. Didnt stay about long did it.
Mactronix



i have a feeling that maybe those gddr4 chips came from the old 2900xt's that got stuck in the warehouse. lol
a b U Graphics card
November 10, 2008 1:36:13 PM

Itll show up when ocing this card, as the ram is already 10% faster, and thats where most of youre ocing is held back, as the core should do ok, and really shine without even ocing the ram
a c 130 U Graphics card
November 10, 2008 7:04:44 PM

wh3resmycar said:
i dont know much about the latencies from gddr3 to gddr5, but i was hoping (actually praying lol) this will put it nearer to the 4870 (especially when overclocked) or at least 10% faster compared to a superclocked 4850 ddr3. guess it wont happen.

thanks dagger for ultimately crushing and stepping on my dream lol, just kidding, thanks for those computation btw.

im PSU limited (supposed to buy the corsair tx-series as replacement from my vx450, with the help from people from the psu section, thanks), and budget limited and considering theres a bunch of games coming out, my 4870 dream is slowly melting away.



You do not need a new PSU to run a 4870. The card uses about 130Watts = 11Amps. Yes the Corsair VX450 has only 1 Pcie connector but they do make adaptors. I just finished reading a review where they tested one with a Q6600 @3.2GHZ 2x HDD 500GB 4x extreme overclocked ram 2x optical drives and an audio card with a HD4870, it didnt even break sweat and performed on a par and better than more expensive options.

mactronix
a b U Graphics card
November 12, 2008 2:29:01 PM

well i did a checked on corsair's website, their very own psu calculator page. when i post my specs it always shows the vx520 as the minimum.

anyway can you show me the review you're talking about? im just 70$ short (thanks cod5 for taking a chunk of my budget), i might get it after a week or two, depending on how good i am at spending my allowance lol.
a c 130 U Graphics card
November 12, 2008 2:51:26 PM

That exact review was in a magazine im afraid i just checked the website an dit hasnt made it there yet so here is a differant in depth review of the power supply, read it and make up your own mind. http://www.hardwaresecrets.com/article/540/1

mactronix :) 
a b U Graphics card
November 12, 2008 3:00:27 PM

The only instances where GDDR4 has been used is the 2xxx and 3xxx series, which doesnt show the improvements on higher clocked ram like the 4xxx series. The only difference between the 4850 and the 4870 is 20% on core and then the ram. The 4870 is more than 20% faster than the 4850......
November 12, 2008 3:42:23 PM



Ugh, I hate PSU calculators. PSU calculators are about as useful as the food pyramid. I don't even touch that many servings of fruits and vegetables in a month but I'm still kickin. Come on...who follows that? I did a PSU calculator for my system and I think it told me I needed 800W....I am using a 650W with no hiccups. Haha, you can all flame me, I am just laying on the sarcasm here.

Anyway on a serious note...look at your system now and figure out if you want to expand it or not and if you are using USB coffee pots and such... :heink:  It is always nice to get parts that don't limit your upgrades but having the min required PSU is just fine. If you get a 520W PSU you can run a 4850 with no sweat...you can even do a 4870....you might regret it down the road though if you ever want to throw in a larger GPU or even two.

Start with ATI's minimum requirements and go from there. It doesn't hurt to get a larger PSU then necessary (you only draw what your system needs) but going overboard would be a waste of money if you pay for wattage that you will never use.

What is your PSU budget? Newegg has some decent deals going on right now. You can probably snag something pretty cheap if you are in the market for one with all of these black Friday deals.

FYI:

ATI's requirment:
450W for a 4850
500W for a 4870
650W for a 4870x2

http://ati.amd.com/products/radeonhd4800/requirements.h...

a c 130 U Graphics card
November 12, 2008 4:40:21 PM

The thing is those of us who know whats what know those ATI system requirements are a load of rubbish. Yes as a consientious forum member i realise that best practice is to follow the manufacturers requirements when recomending or sugesting stuff, However according to ATI the 3850 the 3870 and the 4850 all have the same requirements ??? Now a quick trip over to X-bit Labs or a similar site that records power requirements shows that to be far from the truth.

@ wh3resmycar,
At the end of the day its up to you, The safest route is indeed to go with the official Unit. Personally i would be happy with what you have. However please be sure that you yourself are happy with what you do and that you understand the reasons why. In other words dont just do it because i say so. Read the review i gave you weigh up the pro's and cons and decide for yourself which unit to use.

mactronix
a b U Graphics card
November 12, 2008 4:42:24 PM

thing is i dont want to replace my vx450 because if i do that the only card that i'll be able to buy is a 4850 which makes the psu upgrade pointless.
a b U Graphics card
November 12, 2008 4:46:10 PM

@ mac

yup thats why im doing...

@spin

and thats a good timing for that food pyramid.. especially for me who's 5"10 and weighs 230lbs lol.
a b U Graphics card
November 12, 2008 7:40:21 PM

i swear i saw the 520w variation the first time i tried my spec on there. i mustve bumped my head hard before i did that, or maybe corsair did a minor update..

thanks mac.
a c 130 U Graphics card
November 12, 2008 7:48:36 PM

We got there in the end thats the main thing, glad i could help :) 

Mactronix
November 12, 2008 8:12:38 PM

If you want to know how it will perform look at the regular 4850s that have been factory overclocked to that speed. gddr4 offers zero speed advantage over gddr3, often times gddr3 can overclock further than gdd4, this is utterly pointless.
November 12, 2008 8:45:26 PM

my hope is, we slip past ddr4 and go to ddr5 on the desktop and we all have solid-state harddrives that have a speed of 1gig a second
one can but dream
!