Radeon 4870 or Crossfire 4850s?

[ccubed]

I've been obsessing over new systems in light of the recent GPU war developments. I see that as of 7-3-08 Newegg has several Radeon 4850's selling for about $200 with $25-30 mail in rebates available. The 4870's are going for a uniform $310. So you can get 2x 4850's for about $365 (I'm assuming you can't get the rebate on both cards since they seem to be tied to purchasing another product in order to qualify for the rebate) or 1x 4870 for about $310.

The rebate sale seems to be a response to how popular those cards are as an incentive to buy more from Newegg while you're at it. I do somewhat fear that the price rollercoaster might not be over since Nvidia has been slashing prices like crazy lately, however.

If you were building from scratch and probably intended to use the system for some time to come (not someone who upgrades every 1 or even 2 years) which would probably be the better choice? Or is there a 3rd option that might be more attractive?

 

[Sylvanas]

What motherboard would you pair 2 4850's with? The 4850s will give you better performance than a single 4870 and will only get better with time and drivers. If you are going Crossfire it only really makes sense to pair them in a 16x16 2.0 board like the 790fx/X38/X48, if you are planning on using another chipset like P35/P45 or in between it would be best to get the single 4870.

 

[ccubed]

I was looking at the ASUS P5Q Pro LGA 775 Intel P45 since there was an Asus 4850 with the $30 rebate if you combo the pair. But that mobo isn't an 16x link.

Oddly, none of the pdf's for the rebates indicate on them that you need to buy anything other than the vid card. Of course, I wouldn't really want to gamble on double coupons or not having purchased the corresponding paired product.

Edit: also it seems the Egg knocks 10 bucks off if you buy 2+ at the same time.

 

[Magusigne]

Yeah... p45= Pci 2.0 on 8x/8x you'll want an X48 mobo to hit full potential

 

[ccubed]

I was mistaken about the rebates. They have nothing to do with the combo deals at the Egg. There are just several 4850 cards there that have $20-30 mail in rebates until July 15th. So I could get x2 cards at 159.99 each after rebate.

Too bad there isn't a combination with one of the x48 mobos.

 

[Creig]

This is the question I've been struggling with for awhile now. On the one hand, a pair of 4850s can be had for around $320 after rebate while a single 4870 is still sitting at $300. The performance delta between the two is substantial and would seem to make a decision between the two a no-brainer. But as Sylvanas rightly pointed out, you need a 2x16 PCI-E 2.0 board such as the 790fx, x38 or x48. Going with the AMD 790fx is definitely cheaper as their boards can be found for $135 - $220, yielding an overall price of $450 to $540. But if you wish to go Intel (as I'm sure the majority of people here would), x38 and x48 boards go anywhere from $225 to $350 depending on how fancy you want to get. And that leaves you with a $545 to $670 overall bill. Suddenly the cheap 4850 CF has gotten a heckuva lot less appealing than it did when you were simply looking at a pair of video cards.

On the single 4870 side of things, a simple 16x PCI-E 1.0 motherboard will work just fine with a 4870. I would say that a lot of people currently looking at the new AMD video card offerings already have a system with at least 1 16x PCI-E slot. In that case, the cost of a motherboard can be just left out of the equation and you're looking at just the $300 cost of the card itself. Even if your system is old enough that you need a new motherboard, the excellent P35 chipset based motherboards can be found for $75 to $180. Now you're only looking at shelling out $375 to $480 for your new gaming rig.

Just to throw ANOTHER wrinkle into the mix (as if it needed another), you have to look at your power supply. A decent quad core system with 4gb of memory, a hd, cooling fans and a 4870 will draw around 276 watts. Swapping the 4870 with a pair of 4850s will jump that figure up to 380 watts. While the 4870 system draw is sitting low enough for most decent 500-600 watt power supplies to handle, the 4850CF is getting uncomfortably close to pulling enough power to cause instabilities due to the overall power consumption on each of the 3v, 5v and 12v lines that make up the overall 500-600 watt rating. Overload any one of them and you're suddenly in need of a new power supply, even if the overall system draw is less than total power supply rating. Since there are SO many power supplies available, I'm going to generalize and say that a decent PS for a 4870 system will run $75 to $150 and that a CF system will require one running $125 to $200. Again, this is just a guesstimate based on Newegg prices.

So there it is (at least as far as I've been able to figure out). I deliberately left out the CPU cost as there is such a wide range of prices depending on your pocketbook and performance requirements.

Single 4870 system
Don't need motherboard, don't need power supply - $300
Do need motherboard, don't need power supply - $375 to $480
Do need motherboard, do need power supply - $450 to $630

4850 Crossfire
Don't need motherboard, don't need power supply - $320
Do need motherboard, don't need power supply - $545 to $670
Do need motherboard, do need power supply - $670 - $870



If you find any inconsistencies or errors, please point them out to me and I will gladly change them. Again, this is just a rough idea of the costs involved in upgrading to a 4870 or 4850CF.

 

[Golgatha]

Originally posted by: Powernick50
Yeah... p45= Pci 2.0 on 8x/8x you'll want an X48 mobo to hit full potential

You're talking about a 5% or less difference in performance. If your board can do Crossfire, then it makes sense to get dual HD 4850s over a single HD 4870, as long as your power supply can handle it.

My 975X board does 8x/8x at PCI 1.0 and my benchmarks (I have dual 4850s in Crossfire) are right in line with what's been reported Online. My 3D Mark Vantage score is nearly exactly what's been reported Online, which although not a game benchmark; it certainly stresses my system to the max.

 

[bryanW1995]

the power draw delta is only about 60w since 4850 ~ 110w and 4870 ~ 160w

also, I agree with golgatha on the p45 issue. once drivers mature a bit you should be able to get nearly the same performance out of 2x4850 on a p45 as you could on x38/48. I read the article about the poor crossfire performance on p45, but that is almost certainly due to weaker drivers rather than bandwidth restrictions.

 

[nib95]

This is the same question I've been pondering over. How would the Xfire 4850's run on an old mobo like mine?

 

[Creig]

Originally posted by: bryanW1995
the power draw delta is only about 60w since 4850 ~ 110w and 4870 ~ 1600

The power draw numbers I quoted were copied from the Legit Reviews testing of a 4870 vs 4850 CF system. The only components changed were the cards, yet the 4850 CF pulled 105w more than the 4870 at full load.

http://www.legitreviews.com/article/734/18/

 

[geoffry]

Originally posted by: Creig
This is the question I've been struggling with for awhile now. On the one hand, a pair of 4850s can be had for around $320 after rebate while a single 4870 is still sitting at $300. The performance delta between the two is substantial and would seem to make a decision between the two a no-brainer. But as Sylvanas rightly pointed out, you need a 2x16 PCI-E 2.0 board such as the 790fx, x38 or x48. Going with the AMD 790fx is definitely cheaper as their boards can be found for $135 - $220, yielding an overall price of $450 to $540. But if you wish to go Intel (as I'm sure the majority of people here would), x38 and x48 boards go anywhere from $225 to $350 depending on how fancy you want to get. And that leaves you with a $545 to $670 overall bill. Suddenly the cheap 4850 CF has gotten a heckuva lot less appealing than it did when you were simply looking at a pair of video cards.

On the single 4870 side of things, a simple 16x PCI-E 1.0 motherboard will work just fine with a 4870. I would say that a lot of people currently looking at the new AMD video card offerings already have a system with at least 1 16x PCI-E slot. In that case, the cost of a motherboard can be just left out of the equation and you're looking at just the $300 cost of the card itself. Even if your system is old enough that you need a new motherboard, the excellent P35 chipset based motherboards can be found for $75 to $180. Now you're only looking at shelling out $375 to $480 for your new gaming rig.

If a 16X PCI-E 1.0 is good enough for a 4870 why would 8X PCI-E 2.0 (which offers the same bandwidth as 16X PCI-E 1.0) not be enough for two 4850s? I know that tweaktown review showed a difference but you're giving the same bandwidth to these cards.

Then I suppose you would need a 16X PCI-E 2.0 to take full advantage of a 4870 then too by that logic.

I agree with Golgatha, a P45 shouldn't drag you down enough to justify needing a better mobo if money is tight.

 

[GundamF91]

The 16x or 8x will only really make a difference on high resolution mode. If you keep things reasonable, such as 1920x1200, or 1680x1050, there's virtually no impact. That resolution is more than enough on 24" or 22" monitors.

However, consider the power draw as a bad thing, because you'll be doubling heat source in your PC. If cooling is your concern, then you'll have to spend more money on that. Dont' forget you run a higher power bill, which could increase the cost in the long run.

The bottomline is what you are looking for. If performance is key, get 2x4850. If you want to save money, 1x 4850 is really all you need at this point unless you go to some crazy resolution. You might as well pick up a second 4850 when you truly need it. By then the 4870 probably would've dropped price that you can afford it, or wait for next generation.

 

[geoffry]

Originally posted by: GundamF91
The 16x or 8x will only really make a difference on high resolution mode. If you keep things reasonable, such as 1920x1200, or 1680x1050, there's virtually no impact. That resolution is more than enough on 24" or 22" monitors.

However, consider the power draw as a bad thing, because you'll be doubling heat source in your PC. If cooling is your concern, then you'll have to spend more money on that. Dont' forget you run a higher power bill, which could increase the cost in the long run.

The bottomline is what you are looking for. If performance is key, get 2x4850. If you want to save money, 1x 4850 is really all you need at this point unless you go to some crazy resolution. You might as well pick up a second 4850 when you truly need it. By then the 4870 probably would've dropped price that you can afford it, or wait for next generation.

Thats what I was going to recommend as well, thats what I believe I am going to do.

And if down the road a few really taxing games come out you could get a 4870 and crossfireX the two together I do believe...unless something changed with this generation and you can't mix anymore.

 

[Golgatha]

Originally posted by: nib95
This is the same question I've been pondering over. How would the Xfire 4850's run on an old mobo like mine?

Like smooth butter baby!!! I have the same motherboard as you do. I pull the same numbers within 5% of what's been published Online for CF performance. Oblivion with 8xAdapative AA, 16X AF, and HDR lighting is a sight to behold running a solid 60FPS at 1680x1050.

 

[DaveSimmons]

My approach was a cheap single slot mobo now with 1 x 4870, then if I decide I need more power I'll replace it with a 4870x2 or nv GTX 260 x2 later.

To fully benefit from Crossfire you need a $225+ X48 motherboard, while the $125 I saved buying a $100 P43 board almost paid for the upgrade from 4850 to 4870.

$100 + $310 no rebates vs. $225 + $175 after rebate, and I have more gaming power right now than the person with just a 4850 in his crossfire mobo.

 

[Creig]

Originally posted by: geoffry
If a 16X PCI-E 1.0 is good enough for a 4870 why would 8X PCI-E 2.0 (which offers the same bandwidth as 16X PCI-E 1.0) not be enough for two 4850s? I know that tweaktown review showed a difference but you're giving the same bandwidth to these cards.

Then I suppose you would need a 16X PCI-E 2.0 to take full advantage of a 4870 then too by that logic.

I agree with Golgatha, a P45 shouldn't drag you down enough to justify needing a better mobo if money is tight.

As GundamF91 stated, you don't really notice any appreciable performance degradation going between 16x PCI-E 1.1 and 16x PCI-E 2.0, despite the fact that the 1.1 slots have half the available bandwidth of the 2.0 slots.

From what I've been able to gather, the only time you start to run into performance issues between the two is if you have a game that uses more physical RAM than the card has onboard. Once you exceed that level, then the excess is temporarily stored in your system RAM. Having the fastest available path between the video card and the system RAM will help decrease the amount of framerate hit you will experience. This is not unlike running out of system ram and having to use your swapfile, except that the hit is much, MUCH less than the swapfile scenario since it is being stored in RAM instead of being written to a hard drive.

 

[ccubed]

Originally posted by: geoffry

Originally posted by: GundamF91
The 16x or 8x will only really make a difference on high resolution mode. If you keep things reasonable, such as 1920x1200, or 1680x1050, there's virtually no impact. That resolution is more than enough on 24" or 22" monitors.

However, consider the power draw as a bad thing, because you'll be doubling heat source in your PC. If cooling is your concern, then you'll have to spend more money on that. Dont' forget you run a higher power bill, which could increase the cost in the long run.

The bottomline is what you are looking for. If performance is key, get 2x4850. If you want to save money, 1x 4850 is really all you need at this point unless you go to some crazy resolution. You might as well pick up a second 4850 when you truly need it. By then the 4870 probably would've dropped price that you can afford it, or wait for next generation.

Thats what I was going to recommend as well, thats what I believe I am going to do.

And if down the road a few really taxing games come out you could get a 4870 and crossfireX the two together I do believe...unless something changed with this generation and you can't mix anymore.

Since I'm new to the Xfire/SLI scene, I didn't know you could combo two different card types. I had just assumed you'd have to have two of the same cards to get them to work together. That does make the cheaper 4850 now and wait for an actual personal need to upgrade later approach more attractive, especially in light of the comments that the 8x Xfire vs. 16x performance isn't extremely glaring.