hesitating between 2 mobos for my new AMD

I have decided to upgrade my current CPU to an AMD XP 1800+. I have done some research on prices, performances, and read alot of articles here. I decided on that specific processor because i think that its the one that will give me the most for my money. But to the point, i am hesitating between the two following motherboard setups:
1) MSI 6561 SIS745 motherboard with 512 megs of samsung DDR333 (PC2700)
2) MSI KT3 Ultra motherboard with 512 megs generic DDR266 or 2x256 megs of Kingston BOX DDR266 (PC2100)

The computer place i get my stuff at dosent have any brand name 512 meg DDR266 chips. Getting 2 256's of brandname would be an option, but would cost a bit more. (I live in Canada and all the US online stores charge ripoff prices to deliver here, and only know 1 good computer hardware store that has decent prices)

Now the two systems above would cost me about the same price, but which one would allow me to get the most out of my money. From what i understand, the SIS745 chip is inferior to the one on the KT3 mobo, but it takes high speed ram. How important is it to have 333Mhz ram instead of 266Mhz. Would having a mobo that actually runs at a higher frequency mean that i would have to lower the processor multiplier so it dosent overheat? Or are the speeds of the ram the maximum motherboard speed that the ram will accept, making DDR33 useless to me unless i overclock?

Also, i have read something about the AMD processors being changed from Palomino to t-bred. The T-bred have to be used on special motherboards and with special fans too, right. So would it be better to try and get a palomino or a t-bred. Are the two boards i have selected above certified for the new AMD cores?

And finally, how overclockable can these systems be (SAFELLY!)?


<P ID="edit"><FONT SIZE=-1><EM>Edited by PsStT on 08/10/02 04:49 AM.</EM></FONT></P>
6 answers Last reply
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  1. The SiS chipset is a better chipset in every way except highest overclock speed and highest performance. It's about 5% slower than the VIA, but has none of the bugs VIA is famous for. As for the memory, PC2100 at Cas2 outperforms PC2700 at Cas3, but PC2700 at Cas2 will outperform PC2100 at Cas2 by about 1-2%. The reason is, while the CPU can't use the extra bandwidth, the faster cycle time means the Cas Latency is lower in real time. But if you're overclocking, using the 1:1 ratio will allow you to reach the higher bus speeds needed to get more performance out of PC2700.

    The SiS chipset should do around 166MHz max, the VIA chipset somewhat higher.

    <font color=blue>By now you're probably wishing you had asked more questions first!</font color=blue>
  2. I'll tell ya right now that the KT3 Ultra will support PC2700 no problem. It has the Via KT333 chipset, which supports DDR333. In terms of the SiS 745 chipset being inferior to the KT333, its mostly in terms of performance, usually on the level of 5-10%, barely noticeable. I have heard of issues of the SiS supporting DDR333 properly, and infact, it's possible that there was a <i>decrease</i> in performance when you used DDR333 with a 266FSB. That might have been limited to the ECS branded SiS745 board, or it might have been an actual chipset problem. Try to find reviews of the MSI 6561 that show its performance with both DDR266 and DDR333.

    Now, having said that, the SiS745 chipset offers great stability, and (as I've been lead to believe) has few hardware glitchs and "issues" than Via chipsets. It's cheaper than the Via, and therefore does not have the features the KT3 has.

    The KT3, either the Ultra, Ultra2, or Ultra-ARU (the version I own) supports DDR333 no problem, and if you are up for overclocking, also allows you to run the processor at a 333FSB instead of the usual 266FSB, which is the only real way to get the most out of DDR333 ram.

    As a bit of info. Currently, all AMD Athlon processors run with a DDR266 FSB (133MHz, double-pumped). That means that the 1800+ you plan on getting runs at 1.533GHz, which means a multiplier of 11.5 and a FSB of 133MHz (11.5x133.33MHz=1533MHz). Usually, the RAM runs at the same speed as the FSB. On Athlon systems, that means the 133FSB double-pumped/DDR, meaning DDR266. Running DDR333 means the FSB of the RAM is 166MHz, but this difference from the processor's FSB means that even though the RAM can work and transfer faster, the CPU can't handle it, and the RAM ends up being idle 25% of the time or so. So, running a Athlon processor at a 266MHz FSB with DDR333 memory, usually you'd only get a 2-4% increase in performance (though the performance is about the same on SiS745 boards, I believe). Because the RAM is sitting idle, it's not being used fully, and you're not getting all you can get out of it. Now, it's a little more future-proof with DDR333, since there are rumors that the Barton core (the next Athlon redesign due sometime late fall, early winter) will have a native 166MHz/DDR333 FSB, and the Athlon Hammer that will probably appear around Christmas, maybe a month later, will also support DDR333. That means that those processors will be able to use the DDR333 RAM to its full capacity. But, the current Athlons can also be kicked up to a 166MHz/DDR333 FSB, though you need a good heatsink/fan combo (the AX-7 with a 80MM Mechatronics fan is a quiet enough combo for less than $50). You either need to unlock the Athlon (a messy process, and one that <i>will</i> void your warrenty, especially since it'd be very difficult to remove superglue without leaving traces of it) or you can try your luck at getting a 1600+, maybe even a 1700+ and trying to raise the FSB to 166MHz/DDR333. A 1800+ probably won't be able to make it that high, since that would mean an actual clockspeed of 1.9GHz, a bit out of range even for the newest core revisions. That way would be harder to trace in case you kill the CPU, but again, it will void any warrenty for the CPU, though it might be easier to RMA and get a new one since there is no physical evidence.
    Would having a mobo that actually runs at a higher frequency mean that i would have to lower the processor multiplier so it dosent overheat?

    Simply put, no. Using DDR333 RAM does nothing to affect the CPU or motherboard in terms of frequency. The only way to change frequency is to either unlock the CPU and raise or lower the multipler in the BIOS, or use the BIOS to raise or lower the FSB of the CPU (does not require any unlocking).

    The SiS745 chipset, I don't think, can run in a stable manner at a 166MHz FSB, if at all. Therefore, if you are serious about overclocking, the KT3 is probably the way to go. Also, the KT3 offers a FSB divider of 1/5. What that does is divide the 166MHz FSB by 5, giving you 33MHz, the speced speed of the PCI bus. In other words, if keeps the PCI and AGP slots in spec so you are not overclocking them. That means that the system will remain stable at higher FSB speeds, cause the PCI and AGP cards you have are not overclocked, or not overclocked as much as they would be without the 1/5 divider.

    As to the RAM question. Always get brandname RAM. Never get generic stuff, <i>especially</i> if you have any plans of even a modest overclocking attempt. RAM is one of the worst things to skimp on. Always go with Crucial, Corsair, or Mushkin when it comes to DDR. Those are <i>the</i> brandnames in DDR memory. Kingston is decent, but not the best. Crucial is Micron's factory-outlet store, in a sense. They cater to the value-minded people who want top-quality, high performance parts, but don't need more than modest overclocking ability. Both Mushkin and Corsair cater to the overclockers and performance freaks. Both Mushkin and Crucial offer limited lifetime warrenties, and are usually pretty easy to deal with. I have no experience with Corsair, other than that it's a decent product, if a bit pricey.

    RAM is the biggest (other than a bad/weak power supply unit) stability killer if it's cheap generic stuff, or damaged. Right now, I think I might have damaged a stick of my Crucial when I removed it from my old machine to put it into the new one. I now am having random errors and lockups, where none existed before. All RAM has damage issues, but places like Crucial, Mushkin, and Corsair, test all sticks before they are sold, and will happily replace a stick if its defective. If you want to save money with RAM, stick to the DDR266 stuff, since it's branded, instead of the DDR333 generic grab-bag variety. Its worth the extra shipping to get the DDR333 if you are serious about OCing. Currently Mushkin has 512MB of DDR333 for $169, plus $21 S&H to get it to Canada, Alaska, or Hawaii. Crucial will charge $199 for its DDR333 512MB stick, and $13 for FedEx Internation Prioriy (2-5 days) shipping.... not to mention taxes and whatnot. I'd go for the Mushkin, personally, but in all, either choice is probably better than anything you can get at the shop you are currently contemplating. In fact, the place you're going to might be willing to order and install it for you... you'll just have to wait a couple extra days for it to arrive. Again, avoid generic RAM like the plauge. It's not worth the $20 less or so it costs.

    The KT3 will run the newer T-bred core no problem. I don't think the 745 would be, just because AMD made it required that all T-bred supporting motherboards have the required logic built in to read the on-processor thermal diode and to react to out of spec temps. by shutting down... thermal protection. The KT3 has that, while I don't know about the 745. It probably would run the T-bred without a problem, but it would never be "certified" by AMD to run it. So, if you are that concerned about being able to use the T-bred core, go with the KT3.

    As to the KT3, it comes it many flavors. There is the basic Ultra, which is just a run of the mill board, about the same price as the 745, has USB 1.1 ports, on-board 6-channel sound, and 4 IDE ATA/133 channels (4 IDE devices then). The step up is the Ultra-ARU, the version I have and love. In addition to everything the basic KT3 has, it also comes with 4 USB 2.0 ports (much faster than USB 1.1, good for external harddrives, cd-writers, and large MP3 portables), on-board RAID 0+1 (good if you want to setup a RAID system for improved speed or data protection... the only problem is that the two RAID slots cannot be turned off and used as an extra set of IDE slots, unless you get a modified BIOS... a warrenty voider, but good if you want the most IDE devices possible without using RAID), and the S-bracket, which pretty much adds optical ports for the on board sound. The newest KT3 is the Ultra2, which is pretty much just an updated version of the Ultra, has a new VIA southbride, which has USB 2.0 support built in (the "older" Ultras used a NEC chip to support the USB 2.0 ports, since VIA hadn't updated the southbride of the KT333 chipset yet). Also, it (and the Ultra ARU, though it's not advertised much) is Bluetooth ready. Otherwise, it's the same board.

    Well, that's all I have to say. If I missed anything, or if I created more questions, just ask, and I'll help you as best as I can, or point you in the right direction.

    Edit: As Crash said, the performance differences are slight, and not really noticeable, unless you are a constant runner of 3DMark or something. Now, I have yet to encounter any KT333 bugs, and people seem to think that the KT333 had been altered to avoid many of the issues that cropped up in the pre-KT333 days. My only issue in my RAM, and I know thats the cause, since I've removed the bad stick, and all the problems dissapeared. But yeah, VIA has a not so good reputation when it comes to hardware bugs that usually can't be fixed through software updates. I'd like to think that they are past that, but I'll never know.


    <P ID="edit"><FONT SIZE=-1><EM>Edited by SammyBoy on 08/10/02 04:49 AM.</EM></FONT></P>
  3. wow, some great answers in there. Thanx alot SammyBoy.

    <P ID="edit"><FONT SIZE=-1><EM>Edited by PsStT on 08/10/02 06:24 AM.</EM></FONT></P>
  4. How long did it take you to write that???
  5. "How important is it to have 333Mhz ram instead of 266Mhz."

    I cant claim to be a tech expert or anything but I think there is some benchmarks in tomshardware somewhere (motherbord or RAM guide cant remember which) That shows the difference between 266 and 333 DDR. I am pretty sure though that they dont take into account uping the core frequence for the CPU like sam was talking about.

    I cant remember what they were saying but I know that the differences where small enough in my mind that it wasn't worth the extra cash to get the 333 stuff for me at that time (2.5 months ago). But depends on how much you value that extra bit of speed and cash. :-)
  6. OK dude, I also live in Canada.....check out <A HREF="http://www.pccanada.com" target="_new">Premier Computer Canada</A> aswell as <A HREF="http://www.infonec.com" target="_new">Infonec Computers</A>

    As far as motherboards go.....PERSONALLY i recomend the ASUS A7S333 board to u....i ownt his board..its based on the SiS745 chipset and it is definently a keeper.......

    <A HREF="http://www.anandtech.com/mysystemrig.html?id=13597" target="_new">-MeTaL RoCkEr</A>
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