Rage3D Article - ATi Radeon HD 4870 X2 Review

[Lupine]

The HD 4870 X2 hits our bench with a vengeance, literally sending other components running for the hills. With the rebuild complete, its time to see what happens when the a pair of 4870 GPUs get up close and personal with each other.

Rage3D's ATi Radeon HD 4870 X2 Review

[Jokerzwild]

lol @ the "Good things come in pairs" pic . Nice article!

[Spyhawk]

Nice article guys. Thanks:-)

Ahh yes...one thing I didnt see mentioned is micro-stuttering. How did the 4870X2 do in that regard ?

[traitoR]

I liked the use of descriptive pictures, set the mood for the reveiw.

[aiya]

Originally Posted by Jokerzwild

lol @ the "Good things come in pairs" pic . Nice article!

+1 lol

excellent article!

[AlexV]

Originally Posted by Spyhawk

Ahh yes...one thing I didnt see mentioned is micro-stuttering. How did the 4870X2 do in that regard ?

This is one devilishly complex simple topic

AFR induced inter-frame delay inequality (har har har) has the potential to always exist, since it's tied into the nature of the algorithm. It's also not conditioned by GPU-load, as some mistakingly seem to believe-it's just easier to make sttutery graphs based on Fraps under such conditions. There's also a certain threshold of perception-how much of all this hubris is a placebo effect and how much of it is actually people being bothered. Personally I've seldom noticed it(since I started toying with multiple-GPUs), and when that was the case working with the driver-team took care of it (Overlord was a glaring example). Finally, there are numerous causes for stuttering, and at times stuff gets lumped together under the micro-stuttering umbrella for convenience's sake.

Specifically in relation to the 4870X2, it'll always do better WRT MS when compared to former architectures, simply because it's faster, and as such even if every second frame gets presented sooner than "normal" (there's a bunch of theory that should be discussed about MS...someday, I'll actually publish the article on it...someday), the delta between interframe delays will be small enough to not be discernible by the end-user-this means that the FRAPS graph of doom that sends shivers down spines will look nice and levelled around a low value. There's also the fact that drivers are constantly improving (there's a certain amount of driver magic battling MS behind the scenes).

My personal experience is uninteresting because I don't perceive MS, and I also think it's something that has been blown out of proportion in order to service one or another's interests, as well as due to the dramatic effect the discovery brought (hint, looking at AFR for about 5 minutes makes it clear why MS can exist and how it happens...and AFR has been around the block for a while). So I certainly can't make comparisons involving something i don't perceive...and I also play with V-sync on. However, I aknowledge the existence of the issue, and I also understand why ppl would be interested in it- hence why it's been discussed in the interview with Eric Demers, and why it's one of the topics that are always touched when chatting with guys from ATi.

[caveman-jim]

So, what are the thoughts on where the bottleneck point is for CPU's? 3.6 for an intel C2Q for a 4870 X2 and, what, a theoretical 3.8-4.0ghz for a Phenom, if it could run that high? DH's Zardon has a skulltrail with dual 4.5ghz Quad cores, for GTX280 SLI - I assume he's CPU bottlenecked, because of multi-thread coding not taking advantage of eight cores (a rather small demographic to code to, certainly, now, but in a years time?) and effective FSB and memory bandwidth limitations to feed the cards?

[AlexV]

Originally Posted by caveman-jim

So, what are the thoughts on where the bottleneck point is for CPU's? 3.6 for an intel C2Q for a 4870 X2 and, what, a theoretical 3.8-4.0ghz for a Phenom, if it could run that high? DH's Zardon has a skulltrail with dual 4.5ghz Quad cores, for GTX280 SLI - I assume he's CPU bottlenecked, because of multi-thread coding not taking advantage of eight cores (a rather small demographic to code to, certainly, now, but in a years time?) and effective FSB and memory bandwidth limitations to feed the cards?

Hrm, I don't think there's a straightforward answer to that question, simply because that tends to be game dependent, on one hand, and it's also varies based on how powerful the GPU(s) you're using is(are)-so for a 3870X2 it'd be considerably lower than for a 4870X2. We should also consider resolution/rendering load-the higher both are, the less likely it is for the GPU(s) to burn through their command buffers quick enough to end up stalling waiting for the CPU.

I don't have updated numbers for the RV770, but I did some work with the 3870X2s back in the day, and 3.8-4.2 was the sweetspot on a Yorkfield, so it's probably higher for more modern GPUs.

As for the number of cores aspect, that's also not that easy...let's assume a game is decently threaded, and has a thread dedicated to the renderer and all associated quips, that runs on its own core on a multi-core CPU- it'll be limited (at best, assuming the renderer isn't starved due to resource streaming not going on as it should/ai not yet being updated/something else) by the speed of that discrete core. So that's kindof the quip with the Phenom-even if your game is excellently threaded, the render thread will still run on a not so fast core (comparatively), so you'll still be CPU limited. If there's more ancillary work to be done for that render thread, as mentioned above, the limitation deepens, since there may be wait times associated with getting data needed from the other threads.

So the point was that even if you had a game that split work across 8-cores (DiRT/Grid do this, for example), if those 8 cores would be clocked at 1.8, let's say, you'd still be CPU limited, although your performance would be better than on a single core, since you're reducing the per-core pressure by threading and splitting the work (hopefully, this makes sense). So Zardon's rig is good because it's at 4.5 primarily, and not so much because it has 8 cores- if we consider only gaming. Probably a single Quad at 4.5 would pretty much produce the same results/better ones (Skulltrail is a rather issue plagued platform).

For QuadCF testing I'm using a Yorkfield at 4 or 4.2 (I've not decided yet, or properly tested it for stability), so it should be a good point to see how much CPU may be needed.

[jam2k]

Great review !

Based on my own experience ... Micro stuttering: What ?

[Bibbit]

Originally Posted by aiya

+1 lol

excellent article!

Wow, I reckon a lot of teenagers go to this site, eh? My wife saw this and asked what the heck I was looking at. When I said it was a tech site, she didn't believe me. When I showed her it was she suggested I look elsewhere for this kind of news. I think she's right. You guys really need to grow up. Maybe down the road I'll check back in and see if you've done so, but for now, I'm out of this place. Too bad, I've been using this site since before the join date next to my name. That's a lot of years. Such a shame.

[jam2k]

[Lupine]

Originally Posted by Bibbit

Wow, I reckon a lot of teenagers go to this site, eh? My wife saw this and asked what the heck I was looking at. When I said it was a tech site, she didn't believe me. When I showed her it was she suggested I look elsewhere for this kind of news. I think she's right. You guys really need to grow up. Maybe down the road I'll check back in and see if you've done so, but for now, I'm out of this place. Too bad, I've been using this site since before the join date next to my name. That's a lot of years. Such a shame.

A lot of work goes into these reviews and sometimes, especially when things don't go quite as planned, it can be helpful to approach things with a sense of humor. So while we certainly don't want our content to push readers away, hopefully most of them at what they like, at what they don't, and leave it at that. For the others, thanks for the feedback - we do our best to meet the needs of a varied audience and understand that we can't please everyone every day.

Again, we do appreciate constructive feedback. Toward that end, I've made a thread in the Feedback Forum (click here) for those who have something of value to share in regard to improving the quality of our articles. Thanks.

[DivotMaker]

Originally Posted by Bibbit

Wow, I reckon a lot of teenagers go to this site, eh? My wife saw this and asked what the heck I was looking at. When I said it was a tech site, she didn't believe me. When I showed her it was she suggested I look elsewhere for this kind of news. I think she's right. You guys really need to grow up. Maybe down the road I'll check back in and see if you've done so, but for now, I'm out of this place. Too bad, I've been using this site since before the join date next to my name. That's a lot of years. Such a shame.

Sorry you feel that way...since you felt the need to criticize the site in such a manner, don't let the door hit you where the Good Lord split you.....

I just turned 50 last month, so NO, this site is not just teenagers.....

[Lupine]

Originally Posted by DivotMaker

Sorry you feel that way...since you felt the need to criticize the site in such a manner, don't let the door hit you where the Good Lord split you.....

I just turned 50 last month, so NO, this site is not just teenagers.....

Feedback is good.

Jeez you're old!

[DivotMaker]

Originally Posted by Lupine

Feedback is good.

Jeez you're old!

Feedback is good when it is objective and not unnecessarily negative. While I agree there are a number of young users at Rage 3D, it is certainly not dominated by them and most of them are fairly easy to pick out.

Yep, I am old chronologically....just a kid at heart in a 50 year old body....

[Lender]

Originally Posted by DivotMaker

Sorry you feel that way...since you felt the need to criticize the site in such a manner, don't let the door hit you where the Good Lord split you.....

I just turned 50 last month, so NO, this site is not just teenagers.....

Wow, I turn 50 next month, HAPPY BIRTHDAY to me!!! I've been visiting this site once in a blue moon since about '04, usually through a link posted elsewhere on one of the many sites that have links to reviews around the web. I have to say, I agree that this site is not just for teenagers. BUT, the guy didn't say that, he said it looks like a lot of teenagers visit it. I can't say as I agree to that either, but I do think that maybe teenagers post reviews here. Let's face it, including that picture was an immature thing to do. I felt strongly enough about it to join and post my thoughts. And as for me, I can not say that I consider this a serious site after seeing that review. Maybe it's me, maybe it's because I'm a guy who has been in tech since the early 80's, has an MSDN account that costs $5k+ a year, and is responsible for a large chunk of the financial systems at one of the biggest banks in the US. Maybe I'm just too serious, but I am who I am and I must say that review did not impress me.

NOTE: I tried to post a reply similar to this about 15 minutes ago and it's not showing up, so if I end up with 2 posts, please forgive me.

[SIrPauly]

Originally Posted by AlexV

Specifically in relation to the 4870X2, it'll always do better WRT MS when compared to former architectures, simply because it's faster, .

Agree with this.

[Jokerzwild]

Originally Posted by Lender

Wow, I turn 50 next month, HAPPY BIRTHDAY to me!!! I've been visiting this site once in a blue moon since about '04, usually through a link posted elsewhere on one of the many sites that have links to reviews around the web. I have to say, I agree that this site is not just for teenagers. BUT, the guy didn't say that, he said it looks like a lot of teenagers visit it. I can't say as I agree to that either, but I do think that maybe teenagers post reviews here. Let's face it, including that picture was an immature thing to do. I felt strongly enough about it to join and post my thoughts. And as for me, I can not say that I consider this a serious site after seeing that review. Maybe it's me, maybe it's because I'm a guy who has been in tech since the early 80's, has an MSDN account that costs $5k+ a year, and is responsible for a large chunk of the financial systems at one of the biggest banks in the US. Maybe I'm just too serious, but I am who I am and I must say that review did not impress me.

NOTE: I tried to post a reply similar to this about 15 minutes ago and it's not showing up, so if I end up with 2 posts, please forgive me.

Sorry bout that, you were caught in the spam filter. Welcome to Rage!

[{WOR}lock]

Seriously? That picture offended two people? Wow....

Must be a generation gap thing.

[Jokerzwild]

Well, I'm not THAT old (no offense you fogies ), but I'm far gone from my teenage years and I'd say it doesn't actually offend me. Sure it might be a bit less than professional but IMO it's not unacceptable. This isn't a print review, it's the internet. Everyone's entitled to an opinion though.

[caveman-jim]

Originally Posted by AlexV

Hrm, I don't think there's a straightforward answer to that question, simply because that tends to be game dependent, on one hand, and it's also varies based on how powerful the GPU(s) you're using is(are)-so for a 3870X2 it'd be considerably lower than for a 4870X2. We should also consider resolution/rendering load-the higher both are, the less likely it is for the GPU(s) to burn through their command buffers quick enough to end up stalling waiting for the CPU.

I don't have updated numbers for the RV770, but I did some work with the 3870X2s back in the day, and 3.8-4.2 was the sweetspot on a Yorkfield, so it's probably higher for more modern GPUs.

As for the number of cores aspect, that's also not that easy...let's assume a game is decently threaded, and has a thread dedicated to the renderer and all associated quips, that runs on its own core on a multi-core CPU- it'll be limited (at best, assuming the renderer isn't starved due to resource streaming not going on as it should/ai not yet being updated/something else) by the speed of that discrete core. So that's kindof the quip with the Phenom-even if your game is excellently threaded, the render thread will still run on a not so fast core (comparatively), so you'll still be CPU limited. If there's more ancillary work to be done for that render thread, as mentioned above, the limitation deepens, since there may be wait times associated with getting data needed from the other threads.

So the point was that even if you had a game that split work across 8-cores (DiRT/Grid do this, for example), if those 8 cores would be clocked at 1.8, let's say, you'd still be CPU limited, although your performance would be better than on a single core, since you're reducing the per-core pressure by threading and splitting the work (hopefully, this makes sense). So Zardon's rig is good because it's at 4.5 primarily, and not so much because it has 8 cores- if we consider only gaming. Probably a single Quad at 4.5 would pretty much produce the same results/better ones (Skulltrail is a rather issue plagued platform).

For QuadCF testing I'm using a Yorkfield at 4 or 4.2 (I've not decided yet, or properly tested it for stability), so it should be a good point to see how much CPU may be needed.

Good points. An article I'd like to see is a rundown on where the limitation points are for the current hardware; for example where the bottleneck is for a dual core and quad core rig running a 4670/4830/4850/4870/CF/CFx for small set of applications (like two or three the major engines licensed in games today) at different resolutions - 720p, 1280x1024, 1680x1050, 1080p, 2560x1200 : kinda instant graph showing if you're CPU bottlenecked and so should crank up the AA/AF or if you're GPU bound, and should drop AA/AF, resolution etc.

For example, my rig is a Xeon X3210 intel quad @ 3ghz with 4Gb RAM and a 4850. Running UT3 @ 1680x1050 max details & quality with 4xAA/16AF am I GPU bound or CPU bound? I think I'm GPU bound, as if I OC the core and mem a little I get a nice FPS increase.

[caveman-jim]

Originally Posted by Jokerzwild

Well, I'm not THAT old (no offense you fogies ), but I'm far gone from my teenage years and I'd say it doesn't actually offend me. Sure it might be a bit less than professional but IMO it's not unacceptable. This isn't a print review, it's the internet. Everyone's entitled to an opinion though.

I got a look from the cavewoman when reading it in front of her. I guess the pictures are to highlight the target audience, which I suspect I'm not.

[AlexV]

Originally Posted by caveman-jim

Good points. An article I'd like to see is a rundown on where the limitation points are for the current hardware; for example where the bottleneck is for a dual core and quad core rig running a 4670/4830/4850/4870/CF/CFx for small set of applications (like two or three the major engines licensed in games today) at different resolutions - 720p, 1280x1024, 1680x1050, 1080p, 2560x1200 : kinda instant graph showing if you're CPU bottlenecked and so should crank up the AA/AF or if you're GPU bound, and should drop AA/AF, resolution etc.

For example, my rig is a Xeon X3210 intel quad @ 3ghz with 4Gb RAM and a 4850. Running UT3 @ 1680x1050 max details & quality with 4xAA/16AF am I GPU bound or CPU bound? I think I'm GPU bound, as if I OC the core and mem a little I get a nice FPS increase.

That's certainly an interesting avenue of investigation. The trouble is that tools aren't exactly there yet (for making accurate measurements as opposed to educated guesses based on OCing CPU/GPU, or adjusting discrete settings, as would be the case with what's currently available), at least on the ATi side of the fence (the latest PerfHUD is quite good). Once that situation changes soon-ish, that's something that will be looked at. Thanks for the suggestion.

[sebazve]

excellent review...the pics were really funny jajaja

keep it up.

one question which is cheaper two 4870 on CF or a single 4870X2??

[HonestJohn]

Fantastic Review Alex. First Review that ever turned me on, and my wife said to say thank you by the way.

[narciso]

I suggest the Clear Sky game for the next review The X2 eats for breakfast all games tested, except offcourse Crysis.

[AlexV]

Originally Posted by narciso

I suggest the Clear Sky game for the next review The X2 eats for breakfast all games tested, except offcourse Crysis.

Your wish shall be granted. I've been playing with it for a few days now...it's renderer is quite interesting.

[narciso]

Originally Posted by AlexV

Your wish shall be granted. I've been playing with it for a few days now...it's renderer is quite interesting.

Yep, I also have been playing around with it. It has amazing light effects, but makes the x2 crawl.

[SSXeon]

ahahahah




SOOO HOT!!

Great job guys!

[Treeckcold57]

Hehehe I like that pics too! New R3D 4870X2 article was great!