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MB with ATI Radeon HD 4200 using sideport memory *only*

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  • MB with ATI Radeon HD 4200 using sideport memory *only*

    Hi All!
    I'm going to buy a mother board, one is Biostar TA785GE 128M with ATI Radeon HD 4200 onboard - 128 sideport memory included. I don't want to share my main memory, thus I hope to have almost independent video card, but I've heard that in order to work I must give it some main RAM or computer won't even pass POST...

    Is this problem solved? If not, what's the point of having sideport memory and still share main RAM? May I hope that some time later I'll be able to use sideport memory with dirver (any open source or proprietary...) using it correctly, not requiring me to share main RAM?

  • #2
    Originally posted by Enemy View Post
    what's the point of having sideport memory and still share main RAM?
    Same point as having L3 cache and still using RAM sticks, basically.

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    • #3
      I just checked this with my Asrock A780GXH/128M it doesn't have a radeon hd 4200 but should be similar enough.

      With shared memory disabled the X display is heavily corrupted, same when I set shared memory to 32mb. With 64mb and up it works.

      AFAIK the igp can take advantage of the combined bandwidth of sideport and system ram. So if you only use sideport you lose some performance. I saw some benchmarks that showed a pretty noticable difference.

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      • #4
        Sideport memory is primarily there for low power operation (you don't have to wake up the CPU to access CPU-attached memory). It tends to have a very narrow memory bus and so is not particularly fast. IIRC sideport memory on the system referenced in that article has a 16-bit memory bus, vs 64-128 for UMA system memory and 64-256 for a typical discrete GPU.

        Just curious, what is the reason for wanting to use only sideport memory given that it is the slowest memory option ?

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        • #5
          Thanks for your replies, guys.

          Just curious, what is the reason for wanting to use only sideport memory given that it is the slowest memory option ?
          I thought that then I will have better overall system (not 3D) perfomance, video chip won't be using CPU to access main RAM, and that's like having an external video card.

          I'm not really a gamer, so I don't really need 3D, just looking for a good motherboard, so is this a good choice?
          Won't it lower the overall perfomance to use sideport+main RAM?

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          • #6
            There are rarely simple answers when it comes to performance

            I expect that using sideport + UMA (if the drivers support it, I'm not sure) would improve your graphics performance but might make background tasks run more slowly because of memory contention. I expect your overall perception of performance would be highest with sideport+UMA, followed by UMA only with sideport-only being the lowest. I don't know if the drivers even try to support sideport-only for normal use.

            Once you add compositing into the mix all the performance equations change again, and there it might make sense to have the compositor target buffer(s) in sideport memory and all the normal render targets in UMA memory, but I'm not sure the compositors are sufficiently smart to deal with that kind of arrangement yet. It will make for some interesting tinkering with the open source stack over the next year or so, I think.

            For the moment I would think about sideport memory as a way of boosting graphics performance when used in conjuction with UMA, at least for a desktop system.
            Last edited by bridgman; 09-11-2009, 07:49 PM.

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            • #7
              hmm...
              I expect that using sideport + UMA (if the drivers support it, I'm not sure)
              So, should I avoid buying MB with sideport at all? As I understand it can give me (i'm not a gamer) only driver problems?

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              • #8
                Originally posted by Enemy View Post
                hmm...


                So, should I avoid buying MB with sideport at all? As I understand it can give me (i'm not a gamer) only driver problems?
                Yes! ... Buy Mainboards witout IGP VGAs and Buy an 4350 PCIE and you will have the best Desktop performance !

                IGP are bullshit Sideportmemory are bullshit!

                IGP are only cheap a performance PC isn't cheap!

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                • #9
                  I have such suggested PCI-E card, it is not worth to buy until there is video accelleration for it. until then you could run the onboard using fglrx too. When i try to watch BD media with about 30 mbps then even a dual core E8400 is at 80% or more on each core (with mplayer mt) and tends to lose av sync. vlc would be better from sync but only runs on one core. vdpau+mplayer at least works for video but not fully prefect with a/v sync. Also mplayer currently needs -demuxer lavf for m2ts.

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                  • #10
                    Originally posted by Kano View Post
                    I have such suggested PCI-E card, it is not worth to buy until there is video accelleration for it. until then you could run the onboard using fglrx too. When i try to watch BD media with about 30 mbps then even a dual core E8400 is at 80% or more on each core (with mplayer mt) and tends to lose av sync. vlc would be better from sync but only runs on one core. vdpau+mplayer at least works for video but not fully prefect with a/v sync. Also mplayer currently needs -demuxer lavf for m2ts.
                    i only makes clear that IGPs are bullshit.

                    IGP's stole performance from your CPU and RAM.

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                    • #11
                      No, they are not. Currently the memory has a high bandwith, for low 3d speed purpose they are good, other apps run about the same speed as without.

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                      • #12
                        Originally posted by Enemy View Post
                        hmm...


                        So, should I avoid buying MB with sideport at all? As I understand it can give me (i'm not a gamer) only driver problems?
                        I don't see sideport memory causing driver problems, I just don't happen to know off the top of my head if the Catalyst Linux driver makes use of it today. I think it does, just not sure.

                        IGPs give you a nice inexpensive graphics solution. You won't get as much performance as a discrete graphics card but you pay a lot less as well. Sideport memory gives you another option - a bit more performance for a bit more money, but still less expensive than the cheapest discrete graphics card.

                        In terms of whether to get a board with sideport, I think the question is whether you are likely to upgrade your system by adding a discrete card in the future. If you are, then I wouldn't bother with sideport and save the few $$ for your upgrade GPU. If you are likely to stay with the graphics on the IGP, then sideport memory can give better performance and at least slightly reduce the load on system memory.
                        Last edited by bridgman; 09-12-2009, 11:21 AM.

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                        • #13
                          Originally posted by Kano View Post
                          No, they are not. Currently the memory has a high bandwith, for low 3d speed purpose they are good, other apps run about the same speed as without.
                          thats a pure lie! ... with a true VGA the CPU will always be faster.

                          in other words you can buy cheap slow ram because there is much lower overhead to deliver data from the ram by the cpu into the IGP...
                          Last edited by Qaridarium; 09-12-2009, 11:37 AM.

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                          • #14
                            It is a tiny bit slower, but not that extreme with ddr2/3 in dual channel. There the base speed is high enough. Some nv onboard only handle single channel that will decrease speed a bit. But usally memory thruput is high enough for the cpu that you will not notice the difference. You do not save minutes when you add a gfx card when you compile a kernel or so. You can compare that like when you would use cheap standard memory and somebody else uses oc memory. You only see the diff in memory benchmarks.

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                            • #15
                              I have an Asus m3n78-t with the 790gx and I only use the sideport memory and it runs great. I did notice a lot of corruption when I was using both sideport and ram, until I noticed the speeds the memories were running at -- I overclocked my ram to run at the same speed as the sideport, and voila, no more corruption.

                              I like my ram so I only run on sideport but its fast enough to run everything smoothly without too much harm on the CPU. When running with PCI-E 7950-GX2 with videos load, cpu is at ~20-30%.

                              Same thing with the integrated AMD 3300HD cpu is ~30-40%, so its not top of the line, nor does it have a gig of vram, but it works.

                              Its a great board, don't know about the 4200 but there are FGLRX drivers so it will probably work.

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