4890 vs. 4770 Crossfire

[jmekelb]

I'm still undecided on the GPU for my new build. I've pretty much narrowed it down to these two.

I realize that the logical thing is to buy the 4890 and add a second later if/when I need to. The problem is that I don't think I'll be upgrading for a while so the system I build will probably be the system I have, if you catch my drift.

My concern is that when I crossfire the 4770s, I'll only have 512MB of VRAM available and I'm not sure that's enough.

I could just wait until the benchmarks come out next week but I thought I'd try and get a head start on the input.

i7 920 @ 3.33GHZ
Corsair TX850 PSU
HP w2338h @ 1920 x 1080

 

[Rifter]

what resolution do you game at? if its low the 512MB will be enough, if its high you will be better off with a single 4890 with 1 GB.

 

[jmekelb]

Originally posted by: jmekelb
i7 920 @ 3.33GHZ
Corsair TX850 PSU
HP w2338h @ 1920 x 1080

Thanks.

 

[mhouck]

without any benchmarks, the only constructive thought I have you have already mentioned. The 512mb per card. Not to mention 128 bit. I wouldn't go that route personally.

However, crossfire is coming along. I've seen reviews where 4890 crossfire can scale to 92.3% at your resolutions.
Tech Powerup Crossfire Review

If the 4770's have the same advances in multiGPU scaling that the 4890 has then you might have a good buy. With that said, the 4890 is great at your resolution and you can already find the reviews. If you go on the hot deals forum there is a thread for a MSI 4890 at $185 after rebates. THat's less than two 4770's and you can buy it now.

 

[error8]

4770 with 512 mb of vram on 128 bit will struggle like hell in crossfire at 1920X1080. 4890 is a much, much better choice.

 

[Rifter]

sorry, failed at reading, just got off a 12 hour shift, i would go with the 4890.

 

[jmekelb]

Thanks guys, I think I was getting too caught up in having the newest, hottest, thing. Form before function, you know?

Not that the 4890 is old news, it's been out for what? 3 weeks?

I think you've pushed me back to the original thought of a single 4890 (or possibly bumping my budget for crossfired 4890's).

Only about the 15th time I've come back to the 4890. Maybe it's time I pull the trigger.

 

[TurtleCrusher]

You guys, 512mb of 128-bit DDR3 is not that bad. Especially if it is clocked high.

Just look at the 4650. It almost bests the 3850 with half of the memory bandwidth and old DDR2.

 

[error8]

Originally posted by: Scholzpdx
You guys, 512mb of 128-bit DDR3 is not that bad. Especially if it is clocked high.

Just look at the 4650. It almost bests the 3850 with half of the memory bandwidth and old DDR2.

It is bad, when you're trying to max out games at 1920X1080, in crossfire. The bandwidth limitation tanks performance at that resolution.

 

[betasub]

Originally posted by: Scholzpdx
You guys, 512mb of 128-bit DDR3 is not that bad. Especially if it is clocked high.

True, in less vRAM-demanding situations - and that would allow the 2GPU solution to beat the single 4890. But for gaming at 1920x1080, 1GB of very high bandwidth vRAM is going to be a better solution than 512MB (per GPU) of vRAM with a lesser bandwidth.

 

[AstroManLuca]

Originally posted by: Scholzpdx
You guys, 512mb of 128-bit DDR3 is not that bad. Especially if it is clocked high.

In fact the 4770 uses DDR5.

 

[solofly]

I recommend anybody with a res of 1680x1050/1600x1200 or higher should only consider 1GB cards for gaming. Some will tell you 512 is plenty for that res but I disagree.

My $0.02

 

[cusideabelincoln]

Why is there so much misinformation?

1. HD4770 uses 128-bit GDDR5, which effectively makes it the same bandwidth as 256-bit GDDR3.
2. The HD3850 TROUNCES the HD4650. It's not even a contest: The DDR2 is a big bottleneck. The HD4670, on the other hand, is more competitive, but again the 4670 and 3850 trade blows depending on the settings.

I say stick with a single card unless you're curious about Xfire. The HD4890 would be the way to go.

 

[MrK6]

Originally posted by: cusideabelincoln
Why is there so much misinformation?

1. HD4770 uses 128-bit GDDR5, which effectively makes it the same bandwidth as 256-bit GDDR3.
2. The HD3850 TROUNCES the HD4650. It's not even a contest: The DDR2 is a big bottleneck. The HD4670, on the other hand, is more competitive, but again the 4670 and 3850 trade blows depending on the settings.

I say stick with a single card unless you're curious about Xfire. The HD4890 would be the way to go.

Amen, people see "128-bit" and freak out, but that's not the whole story to memory bandwidth.

Anyway OP, the 4770 Crossfire is probably going to be much faster until you run into memory limitations (both in bandwidth and capacity), which I'd imagine you'd hit more often than you'd like at 1920x1080. I'd go with the 4890 for now, as even though it will be slower, it will still handle your resolution very well and handle future games better.

 

[cbn]

Originally posted by: error8

Originally posted by: Scholzpdx
You guys, 512mb of 128-bit DDR3 is not that bad. Especially if it is clocked high.

Just look at the 4650. It almost bests the 3850 with half of the memory bandwidth and old DDR2.

It is bad, when you're trying to max out games at 1920X1080, in crossfire. The bandwidth limitation tanks performance at that resolution.

Is this because both GPUs would be using one 128 bit interface? (not two 128 bit interfaces)

 

[lopri]

Get a 4890 and call it a day. Comparing a 4890 and a 4870 is like comparing an E8400 and an E6600.

Edit: Nevermind. I mistook 4770 for 4870.

 

[error8]

Originally posted by: cusideabelincoln
Why is there so much misinformation?

1. HD4770 uses 128-bit GDDR5, which effectively makes it the same bandwidth as 256-bit GDDR3.

4770 with its ddr5 on 128 bits has 51 GB/sec memory bandwidth, which is even less then what 8800 GT has to offer (57 gb/sec), with its ddr3 at 1800mhz. It doesn't all comes down to memory bandwidth, but I would always choose 1 gb of vram 4890 over 2X4770. Even if the bandwidth proves enough, the small 512 mb doesn't cut it for high resolutions and levels of AA.

 

[error8]

Originally posted by: Just learning


Is this because both GPUs would be using one 128 bit interface? (not two 128 bit interfaces)

Each GPU has its own set of 512 mb of vram. But if one set has the data mirrored from the first one, memory doesn't add up, so you're left with 512 mb, that being one of the bottlenecks.
The bandwidth however, can be considered 128X2 bits, 51 gb/sec X2, which is 102 gb/sec, since both gpus are moving data through each 128 bit memory bus. But 102 GB/sec is less then 124 gb/sec of what 4890 has.