ATI Radeon HD 4000 Series discussion

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Originally Posted by AliG

yes and this is something you will be hearing in the near future with that knowledge
http://blogs.nitobi.com/alexei/wp-co...nt_of_fail.jpg

that or "Aloha! Welcome aboard the failboat! We expect to be sinking in 9 hours, enjoy your trip!"


In other words, if it doesn't make sense, generally its not true

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That's a nice ship

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Originally Posted by Yukon Trooper

2GB of memory won't be beneficial, at least in a gaming environment.

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So what are we looking at a 1GB 4870x2 available at launch or less? Also will the 1GB gddr5 x2 cards cost alot more then the 512mb versions? Anyone have any idea of the price at this time or is a it a guessing game at the mo?

What do you mean 512mb x2? There's only going to be a 1gb gddr5 x2, unless if AIBs decide to give a card 2gb of memory, but that shouldn't be necessary if the shared memory thing is true as that is essentially the same as 2 1gb 4870s in xfire

But that shared memory is probably not true....
Although I do hope it is, but I'm pretty sure it's not :(.

BTW, why is everyone suddenly so concerned about memory size on these cards, if history tells us anything then we won't have to worry with 1GB for at least another year. For the ATI cards that is, it's a bit different on the NVIDIA side atm.

Any chance of a 4780 or 4870x2 AIW? :D Should I hold my breath? I miss them. :(

That shouldn't be needed if clamshell mode is used in GDDR5 application in HD 4870 board. Problem is, it hasn't been implemented in the reference board at the moment IMHO, perhaps the AIB will implement it later in their own version of HD 4870 card -in house designed PCB ala HD 3870 Toxxxic from Sapphire, so the existence of 1 GB HD 4870 won't solely be determined by the availability of 1 Gb GDDR5 chip.

CJ@B3D confirms HD4870 is fast and beats GTX260 in some cases

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Originally Posted by CJ

I also have the Vantage scores of a single HD4870. Heck, I even have one of those damn thingies running in my comp right now... And compared to a similar system (albeit that one has a faster CPU) it manages to beat the GF9800GTX by a very healthy margin (not using the cheat-drivers) and in the feature tests it is almost on par (FT3) or even manages to beat the GTX 260 (FT1, FT2, FT5, FT6). HD4870 is fast.

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Link

It's just that I don't put much value in 3Dmark scores, not for buying a gaming card at least. I would if I were to aim for some kind of overclocking benchmark world record or something like that, I'm just not into that.
So -->> waiting for game benchmarks is all there is to it and the card is supposed to be unwrapped in 2 days anyway. Not doubting the fact that it's fast though, I'm quite sure we won't be disappointed.

Well the feature tests on Vantage are pretty good at seeing the different parts of the card (fill rate, shader performance, etc.) and those look promising (since the 4800's always seem to lose at the GPU cloth test anyways, but it beats the GTX260 at all the other tests so it has a lot of power)

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Originally Posted by azza21

So what are we looking at a 1GB 4870x2 available at launch or less? Also will the 1GB gddr5 x2 cards cost alot more then the 512mb versions? Anyone have any idea of the price at this time or is a it a guessing game at the mo?

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512MB at launch for sure, and I think 1GB to follow soon after. Due to price, availability, demand, and practicality, a 2GB version will probably never see the light of day. If there is one, it will probably be way after initial launch due to the above reasons.

As for price, I think we'll hear many different numbers up until launch, but so far I believe it's estimated in the $500 range. However, considering AMD's recent success and Nvidia's decline in the stock market, and the possibility of the X2 stomping the GTX280, we may see a card as high as $700.

I want a 4870, but this has me worried.
I'm still on PCI-E 1.1 16x which is basically PCI-E 2.0 8x. 4870 will require more bandwidth than 4850, and if a 2.0 8x slot isn't enough for one 4850, then 4870 will choke. Not good.

We were arguing over this a page or so back...

And that tweaktown review is the only review that is showing such poor scaling on a P45 chipset compared to a X38/X48. It can make a difference with flight simulator X but that is about the only game I can think of.

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Originally Posted by Your_Boss

Any chance of a 4780 or 4870x2 AIW? :D Should I hold my breath? I miss them. :(

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AIW was killed awhile ago...
It shouldn't be missed.

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Originally Posted by Helmore

But that shared memory is probably not true....
Although I do hope it is, but I'm pretty sure it's not :(.

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Shared memory is most likely clamshell mode for GDDR5.

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Originally Posted by spursindonesia

That shouldn't be needed if clamshell mode is used in GDDR5 application in HD 4870 board. Problem is, it hasn't been implemented in the reference board at the moment IMHO, perhaps the AIB will implement it later in their own version of HD 4870 card -in house designed PCB ala HD 3870 Toxxxic from Sapphire, so the existence of 1 GB HD 4870 won't solely be determined by the availability of 1 Gb GDDR5 chip.

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I take it you understand the whitepaper?

Why would it need to be "implemented" on the board?

ffs wot is clamshell mode? :lol: is that like put-head-in-sand-mode?cos that's the mode i run in :hehe:
where's my macbook.

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Operation in clam shell mode has no impact on
system band width.
Example: System configurations with 512M GDDR5 device using a controller with 256 bit interface:
A) 8pcs of 512M GDDR5 in standard mode ➔ Frame buffer: 512 MB
B) 16pcs of 512M GDDR5 in clamshell mode ➔ Frame buffer: 1 GB

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from "the whitepaper" link...

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Originally Posted by adamsleath

ffs wot is clamshell mode? :lol: is that like put-head-in-sand-mode?cos that's the mode i run in :hehe:
where's my macbook.

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Haha :rofl::ROTF:

Looks like i need to do some reading...:rolleyes:

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Originally Posted by LordEC911

AIW was killed awhile ago...
It shouldn't be missed.


Shared memory is most likely clamshell mode for GDDR5.


I take it you understand the whitepaper?

Why would it need to be "implemented" on the board?

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Clamshell mode for GDDR5 does not do what you say it does. Clamshell mode allows for a single memory controller to access 2 memory chips, it does not allow for 2 memory controllers to access a single chip. So no shared memory through clamshell mode because a single memory chip can only cope with 1 controller and not 2, which is need for your shared memory approach.
Basically clamshell mode allows you to use the same 512Mbit chip for both a 512MB 256-bit card using 8 chips and a 1GB 256-bit card using 16 chips. That's also what spursindonesia is referring to.

Thermalright has updated their VGA Compatibility charts stating that many cooling solutions work on 4850/4870.

I might get the V2. I'm a sucker for copper :). http://www.thermalright.com/new_a_pa...age/v2_mcl.htm

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Originally Posted by Helmore

Clamshell mode for GDDR5 does not do what you say it does. Clamshell mode allows for a single memory controller to access 2 memory chips, it does not allow for 2 memory controllers to access a single chip. So no shared memory through clamshell mode because a single memory chip can only cope with 1 controller and not 2, which is need for your shared memory approach.
Basically clamshell mode allows you to use the same 512Mbit chip for both a 512MB 256-bit card using 8 chips and a 1GB 256-bit card using 16 chips. That's also what spursindonesia is referring to.

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Thank you, that makes more sense.

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Originally Posted by Helmore

Clamshell mode for GDDR5 does not do what you say it does. Clamshell mode allows for a single memory controller to access 2 memory chips, it does not allow for 2 memory controllers to access a single chip. So no shared memory through clamshell mode because a single memory chip can only cope with 1 controller and not 2, which is need for your shared memory approach.
Basically clamshell mode allows you to use the same 512Mbit chip for both a 512MB 256-bit card using 8 chips and a 1GB 256-bit card using 16 chips. That's also what spursindonesia is referring to.

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thank you, lets stop spreading this nonsense. clamshell mode has nothing to do with letting 2 gpus share memory, if it was that easy it would have been done already.

@LordEC911, i don't think the reference HD 4870 PCB is designed to accommodate 16 GDDR5 chip on it.

@Helmore, thx for the kind explanation mate, appreciated. :)

Is the release date for 4870 still on the 25th? Or has it been pushed back?

25th is the day still I believe

cannot wait

Can somebody explain to me the differences between the 4850 and the 4870?

From what I understand they've got the exact same core, only different clocks which the 4850 will easily reach wit a bit of water.

The memory, though, the 4850 has 512mb clocked at 990mhz while the 4870 has 512mb clocked at 900mhz....

I know the latter has gddr5, but is it actually faster at 900mhz than GDDR3 is at 900?

Yes, GDDR5 operates at 900Mhz but its effective memory is actually a multiple of 4 so GDDR5 900Mhz = 3.6 Ghz effective. GDDR3 at 990 MHz = 990 x 2 = 1980 Mhz effective.

Also, the 4870 operates at a 20% higher clock, has a dual slot cooler, but requires 2 x 6 pci-e pin connectors.