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I don't understand HyperTransports

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March 19, 2009 8:32:21 PM

I am sorry to ask, I have googled, and searched toms threads, and amd overclockers and fanatics and all this stuff and no one answers the question...

What is a HyperTransport to a FSB Megahert? I really like the reviews on the 2.7ghz kuma black edition, but I don't know what kind of ram or MoBo to buy because I don't understand the formula to identify what I need for 3,600mhz HyperTransports...

Can someone fill me in on what 3,600mhz HT's are? What kind of RAM syncs with that? I want to build this thing and torture it, see how it goes against my OCed e8400.

Thanks!
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March 19, 2009 8:46:33 PM

Quote:
What is a HyperTransport to a FSB Megahert?


I'm not sure what your asking here. HT is similar to the FSB, as they both connect the CPU to the motherboard. The numbers aren't coverable as they mean different things.

Quote:
Can someone fill me in on what 3,600mhz HT's are?


Thats the speed of the HT bus. Unless you really want to know how it all works, I wouldn't worry about it. AMDs have an on chip memory controller, so RAM speed is important to them. Get DDR2-1066 and don't worry about the numbers. DDR2-800 will also work, but will be a bit slower.
March 20, 2009 4:43:47 PM

Ty forty seven for explaining what kind of RAM I need, but I would like to understand, how do you know that I need 1066 RAM. I mean I understand HT's connect similar to a FSB. With intel its simple, I have 1333 FSB, its quad pumped so if i take and divide that by for the core clock speed is 333, I then OCed it to 400 core. Then I took my DDR2800 RAM and slapped it in there, no OC so it would run synced. Thats simple to me. But throwing 3,600mhz on a AMD chip, I am like wtf? I know they are only dual pumped, but that still makes no sense its way to high. The motherboards are all rated 2,600mhz as well, so I am really skeptical.

I would really appreciate it if you could elaborate just a tad, I just need to know what those numbers are telling me so i know what to get, I will blow it up myself OCing and learn, I just want the right stuff.

Thanks again man.
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March 20, 2009 9:02:41 PM

Voodoo magic.

For AM2/AM2+, the math isn't something I fully understand. CPU multiplier divided by half, rounded up if need be. Many try to stay near DDR2-800 speeds, but because the memory controller is on the chip, DDR2-1066 is faster. (if you can get it that high.) Hopefully someone else can explain better.
March 23, 2009 7:27:13 PM

I understand how its dual pumped instead of quad... I just can't get "that" answer i am looking for from anyone. It's frustrating, but I just bought the whole rig. I have no idea what I am doing. I hope I don't blow it up, but I am going to try and take the 7750 2.7ghz kuma black edition to 3.5 ghz on a ASRock A780FullHD board. I got DDR2-1066 OCZ Gaming ram to go with it. I really wish I could get some more info on these AMD speeds though.

Thanks for still trying to help though, maybe an AMD fan will come through...
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March 24, 2009 2:36:13 AM

What fields are available to you? The 2.7 Kuma has a 13.5 multiplier correct? If you can hit 260, you'll have 3.5GHz. Don't forget to move the LDT setting down (or whatever AMD is calling it these days) so that the HT bus doesn't exceed where its supposed to be. (old days was 1GHz, I'm assuming you don't want it crossing 3.6GHz?) Check the forums, I'm sure there is an overclocking guide around here somewhere.
March 24, 2009 9:44:02 AM

You don't need to worry about the HT. Overclocking the NB can help, but overclocking the HT doesn't really do much. The 7750 is a Black Edition, so for overclocking you don't even have to worry about the memory speed, hyper-transport, etc. Just bump the multiplier. Although you're probably not going to be able to hit 3.5GHz... I've heard the 7750s max out at around 3.2Ghz, maybe a bit more.
March 24, 2009 9:46:34 AM

4745454b said:
What fields are available to you? The 2.7 Kuma has a 13.5 multiplier correct? If you can hit 260, you'll have 3.5GHz. Don't forget to move the LDT setting down (or whatever AMD is calling it these days) so that the HT bus doesn't exceed where its supposed to be. (old days was 1GHz, I'm assuming you don't want it crossing 3.6GHz?) Check the forums, I'm sure there is an overclocking guide around here somewhere.


Overclocking guide for AMD "Black Edition" processors:

1) Bump up the multiplier
2) Increase voltage as necessary
3) PROFIT!
March 24, 2009 9:50:33 AM

Oh, one last bit. The HT is NOT the AMD equivilent of bumping the FSB to overclock. That would be bumping the Core Clock, or whatever it's called... I can't remember. It'll look just like a FSB number would in the BIOS, and it will probably be listed right before or after the multiplier. The HT is just that, the HT, and nothing more. If I recall correctly, in any case...

Oh, and I forgot one last thing. As I said, you can overclock the HT, even though it doesn't do much, but it must always be greater than or equal to the NB speed.
March 24, 2009 12:08:09 PM

Ok great, alot of info. So I am getting the assumption that faster ram is better with the AMD processors, but I should not worry about trying to sync it? Forty seven you said something about the memory controller is on the AMD chips? I am guessing the AMD chips gauge what they need automatically?

@EQPlayer, I am glad you said HT's don't overclock the equivalent of the FSB on intel, which I wouldn't assume I would need to mess with anyway if I shouldn't be worried about RAM synchronization. So I only really need to mess with the multiplier...

Like I said, this is my first AMD overclock. I am going to experiment with it a bit before I go slapping a gaming GPU in this thing. The board was fairly cheap, as was the processor. I am not worried about blowing any of that up to much really, I just have a desire to learn the tricks to these price effective creatures.

I am going to look around a bit more, see if I can pull out anything. I would like to contribute, the way you two have for me. Its hard to find info on AMD's that go into detail like Intel's.
March 24, 2009 1:43:35 PM

You start with a 'HT Reference Clock' which gets labled in alot of BIOSes as FSB or just Bus speed. This generally runs at 200Mhz, unless your OCing. Then you will have a CPU Multi, HT Multi, and NB Multi. HT should be between 2000-2600Mhz, depending on if you have an older K8 or newer K10 proc. Also, ensure that your NB is =< HT.

Memory speed is a little different on AMD systems than it is on Intel. The memory speed is determined by the CPU clock speed rather than from bus speed. Google searching for AMD Memory Dividers should give you a good idea of the formula to determine memory speed, but Ive found its easyer to set a lower speed (i.e. DDR2-667 for DDR2-800 memory) while overclocking, then keep an eye on it in CPU-Z and adjust down again as needed.
March 24, 2009 3:20:28 PM

Hmmm, ok yeah i definitely bought the DDR2-1066 RAM, so I can underclock it and increase the timings safely i think. That makes alot of sense though, so my memory is based off clock speed instead of HT's. Now here's a question I kind of started with except the fact that I have actually learned alot more... Should I keep my RAM and Processor in sync. Originally I heard that AMD syncing was MORE important then Intel's, but I got the vibe on this thread it was less important...
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March 24, 2009 3:32:37 PM

More important, as is having faster memory. Because the memory controller is on the CPU, the faster your memory can go, the faster the system will be overall. Unlike older Intel systems, there isn't a slower FSB the memory request has to travel over. Memory request go straight from the memory to the CPU. No north bridge or FSB to slow down on.
March 24, 2009 4:18:57 PM

Ok cool, so that memory I got I am assuming was a good choice. Now I am so excited to get all the parts in. I will definitely post numbers, temps, and stability. I have heard of someone taking this 2.7 kuma B.E. to 3.5, on the same board. So we will see. I am going to see if I can find a good number crunching and just continue research until I have the equipment.

Thanks alot everyone, I am seeing some of the differences now and I feel alot more confident.

This is what I will be throwing together...
-AMD Athlon 64 X2 7750 Kuma 2.7GHz Socket AM2+ 95W Dual-Core black edition Processor
-ASRock A780FullHD AM2+/AM2 AMD 780G Micro ATX AMD
-OCZ Reaper HPC 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 1066
-Western Digital Caviar RE WD2500YD 250GB 7200 RPM SATA 3.0Gb/s
-CORSAIR CMPSU-450VX 450W ATX12V V2.2 80 PLUS Certified Active PFC
-Rosewill Wind Ryder RZLS142A-P BK Dual 120mm Cooling Fans and Mesh Design Front Panel Steel ATX Mid Tower

Total cost (including non-listed items except GPU and Cooler) 307.52, including shipping and tax
March 27, 2009 2:43:49 PM

Bahhhh. Ok I put it together... I am a little confused now. CPUz is reading 1700 HT (guessing thats hyper transports) 200mhz FSB (I didn't think there was a FSB....) and what is really tripping me out is its reading my 1066 ram as 533...

Is this the motherboard? I know we discussed before about how the memory speed is controlled by the chip. Would this be the cause? Either way its not matching up its a 3:4 ratio.

Should I try setting the memory manually to 1066? Or should I leave it alone? Also what is up with the HT's? Should it read 3,600 on CPUz. Does anyone have a AMD you can relate to what I am talking about, maybe help me understand?

Other then that, it went shockingly well, and the PC feels fast even before OCing.
March 27, 2009 9:08:45 PM

Manually set the memory to the correct speed, the mothertboard won't always do it for you. And no, your HT is fine. The "FSB" in the BIOS is the CPU reference clock.
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March 27, 2009 9:14:07 PM

I think you're ok. I know the memory needs to be doubled (DDR), so 533MHz IS 1066MHz. Same might be true with the HT, 1700 bi directional is 3400 total.
March 27, 2009 9:37:44 PM

DO NOT try to set your memory at 1066 if it's showing 533. It probably won't work, and is just as likely to never work. Many BIOSes show the actual clock (1/2 of effective) instead of effective clock (which is what we always talk about).
March 27, 2009 10:30:15 PM

Well no. My CPUz is showing 533. CPUz I thought was good for showing base and true values. It shows everything as true/base on my gigabyte board...

I think it should show 1066, because CPUz does not split it down I don't think. It should show me what I actually have in there.

I am going to try to mark it up. Hopefully the consequences are not kaboom.
March 27, 2009 10:37:40 PM

ohhh wait, its running at 266mhz... no I am confused. Wierd thing is, its changed the cycles to 3-4-4-10. I am really feeling like something is automatically changing it.
!