Mobility Radeon HD 5870

I recently received a sparkly new M17X R2 as a replacement for my older XPS M1710. As I have been benchmarking and testing out my system I have found lower then expected scores and general performance for the video card.

After loading GPU-Z I noticed that the graphics bus is set to 8X not 16X that the card is capable of.

2hrs and 3 dropped calls later I was finally able to speak with a very helpful Aleinware tech who informed me that these cards will only operate on a X8 bus because the motherboard limits the single cards to that speed. He said 2 cards at X8 = X16, even though the card is more then capable of X16 the motherboard is limiting it.

I'm kinda upset about this.

Should I be?

Yes this system is in most circumstances faster then my XPS M1710, but I feel ripped off that Dell has deliberately limited the PCI-E to X8 in single GPU configurations. Its like being given a Ferrari and then told you can only drive it on single lane bike paths.

Replacement specs:
Special Edition Red, I7 620M, 4GB 1066 RAM, 5870 Mobility HD, 250GB HD, 1920x1200 RGB LCD.

 

this is correct, and even still this is one kick laptop, I would not lose sleep over it.

The PCI-e runs a 16x for one card, or 2 x 8x for two.

 

The PCI-e controller built into the CPU is the reason why the cards are limited to x8 times two. That controller only has provisions for 16 lanes, so when you have two cards connected, it splits them in two, giving x8 for each. Intel would have to change the PCI-e controller built into the CPU die and that isn't going to happen any time soon.

As unbelievable as it sounds, a PCI-e 2.0 x8 connection is more than sufficient for these cards. The benefits from having them run at x16 would be very, very minimal.. so even if you only have a single card, it's not really a big deal that it's only running at x8. While I agree that a single card *should* take advantage of all 16 available lanes, you're not really missing out on anything.

 

mmm why does mines say ''PCI-E 2.0 x 16 @ x1'

and youres is x8?

do these values change?

 

adrian, yours has crossfire.

Mstrong, it is what it is. Can't feel to bad though. It's better than what you had, so while you were given a ferarri to drive in the bike path, you, recieved it as a replacement for your ford temp. At least you can pick up the ladies on the bike path with your ferarri.

 

lol i like youre thinking ;p

so mines is normal, to have x1 on each?

 

I am concerned by this, as a single 5870 configuration also shows x8. why would the cpu do this when there is only one GPU present?

 

i wouldn't be concerned by this. This is a restriction of the motherboard when crossfirex is enabled. This is the same thing you see on any crossfire motherboards. Some motherboards limit the second card down to 4x + 8x, which is even worse and gives you near to no benefit.

8x+8x is actually very good for crossfire purposes. (when the card is running in single card mode you'll notice it running at 16x) like mentioned above.

There are plenty of desktop benchmarks you can see to easy your mind about performance issues with different crossfire configurations. This is why alot of people also prefer 1 powerful single card solution to multi card solutions. (motherboards being as pricy as they can be for these options).

long story short. Don't sweat over it.

as for the guy above me. I haven't been able to test if the 5870 single card shows up as 16x or 8x so someone will have to confirm this. Try rebooting your system with crosffire disabled. That might fix the problem otherwise that might be something to be concerned about.

 

i only have a single 5870, and it is still limited to 8x. you sure i shouldn't be concerned?

http://imgur.com/20soS.png

 

I would be concerend why your card is only running at 8x in a 16x PCIE slot. GPUZ shows your at PCIE 16x 2.0 @ 8x 2.0 So your interface isn't the problem its the setting your card is running at. Did you try to reboot in single card mode maybe pull the battery and run the power button down for 10 seconds. If that still doesn't fix it then. I would have someone else here confirm what they are seeing and if yours is the only one stuck at 8x i'd complain.

You have the most recent bios btw?

 

You're saying that your new M17x only outperforms your M1710 in most instances? That can't be true. My M17 was approximately 486,748 (exaggeration) times faster than my E1705 with a 7950GTX and a T7600. You're talking about a HUGE technology jump in both the GPU and the CPU. You also didn't provide any numbers either. That would help determine if there's an actual problem.

 

I'm not sure what you mean by single card mode. I only have one Mobility 5870. I plan on getting a second one in the future, but I only have one right now. The second card slot is empty.

I'm running BIOS A05

 

What kind of scores are you getting on your benchmarks?

 

Show us Vantage runs, maybe 06 too.

 

Alrighty, give me a moment.

 

Hi Mstrong

My M17x setup is the same with PCI-Express 2.0 x 8.

It is all too common on desktops to have the 1'st slot 16x and the second slot 8x. Some enthusiast motherboards have the 2'nd slot as 16x as well. My board EVGA SLI X58 LE has 8x on the second PCI just like the M17x. The EVGA SLI X58 has 16x on the second slot.

Have read there is probably about a 10% difference between x8+x8 vs x16+x16

If you only have one 5870 your card will use full 16 lanes. If two cards they will share the lanes. With lower end cards it really didn't matter as much. The newer cards running at higher resolutions will see more of a difference between the x16 vs x8.

 

http://imgur.com/hTmv1.png

 

seems normal, what exactly are you having trouble running

 

I don't find it acceptable that a PCI-e 16x card is being forced to run at 8x because the designers of the laptop assumed everyone would be using two cards.

When only one card is present, it should be running at 16x.

 

Mine shows the same thing, and honestly do you see any performance drop because of it. All you know it could be running at 16x. You've already gotten it as a replacement for an m1710 and it beats the pants out of it so why are u complaining.

 

I'm not the Original Poster. I paid 4,000 for my laptop.

 

Point remains how do you even know it doesn't run at 16x or even makes a difference in performance. As far as I can see it offers the same performance compared to other manufacturers with 5870m.

 

The comprehensive specification of the M17x R2 is a Graphics bus PCIe x16 bus supporting x16 PCIe MXM 3.0 graphics cards. (MXM) is a standard graphics interface for PCI Express systems. It has two version A & B. The M17x R2 can use two MXM 3.0 Type B compliant cards with total power budget of 150 W.

The M17x R2 has a Mobile Intel PM55 system chipset. The Core i7 Mobile Processors are suppose to have One, 16 –lane PCI Express port configurable to two, 8-lane PCI express ports. Because of the PM55 I don’t think dell has a choice when CF other than to go x8+x8. BUT I don’t understand why when only one card is used they are not utilizing the full 16 lanes.

To answer the original post Mstrong should not be upset because ALL the Core i7 Mobile processors support configurations of 16 PCI Express 2.0 lanes per GPU or two sets of 8 PCI Express 2.0 lanes.

 

So i am new to these forums and i finally have my m17x r2......i'm the happiest man alive, don't know how i got by not owning one of these. Anyway i have a question.....I don't know if anyone on the forums plays League of Legends......(great game btw) i've noticed on the loading screen right before the game starts everytime the loading percentages change the screen kind of blinks i should say? brighter then lighter.....is this an issue with my computer?? thanks again.....and its great to have a commmunity there that can help

 

I think the Intell P55 Express Chipset has limitations and for this reason Dell has decided to use 8x for a single PCI-e x16 GPU. If they ran a single GPU in 16x I think it would make inoperable for all x1 cards (tv tuner, wireless card, audio card). This is due to the limitations of the Intell P55 chipset.

 

Hi jjyoon

I know M17x R2 customers complained to Dell about game flickering months ago and I think this was fixed with a bios update. Best way to get more information is by posting a new thread. At the time they said to disengage turbo mode in the bios. If it is only happening during one game I wouldn't worry about it.

 

You all missed the point that these cards sit on Gen2 slots in the M17x (at least my R1 is that way, will know in a week or so when my R2 arrives if it is, too). PCI-E Gen2 has double the bandwidth, so at 8x you're actually getting the same bandwidth as 16x. You won't notice any difference from a 16x port, so nothing to worry about with regard to that.

 

The R2 uses a PM55 chip set, so it is PCIe 2.0, however the Pm55 as previously suggested, only has 8 lanes. the I7 has 16 lanes, which is what the GPU's run off of in 8x2 mode.

PCIe 1.0 16lane bandwidth: 4GB/s
PCe 2.0 8 lane bandwidth: 4gb/s

for reference AGP 8X is 2.1GB/s , the cards get plenty of bandwidth for sure.

 

Just for the sake of curiosity, someone should ask one of the m15x owners that installed a non-Dell 5870 what their card is running at. Could also compare it to a Dell 5850, too.. might reveal if it's the cards themselves that are locked at x8 or if it's the system doing it. I realize that the m15x is a single-card system, so if both cards end up showing x16, it probably won't tell us very much.

Personally, I'm suspecting that the cards were intentionally locked at x8 as part of the modifications that were needed to make them work with CrossFire. Dell may have had to lock them there because they weren't properly rate-adjusting down on their own when two cards were present, as silly as that would be.

The x8 operation is still a non-issue though, so it's probably all just a waste of time. XD

 

I am building a desktop a intel i3. For my nephew. It will start out as a single intergraded gpu. It will support two card in ati crossfire 8x. But single card 16x. Thing is the two gpus 8x are faster then one card at 16x. Becuse they are spliting the work into two grapics cards.