my DDR500 memory only shows up as DDR400 ?

[Vesper8]

hey everyone.. a few months ago i upgraded my ram and bought 2gb of pcz platinum EB ddr500

i got a decent performance hit from it but i was always bothered by the fact that when my system boots up it detects my memory as DDR400

i once tried to change the 400mhz to 500mhz in my a8n-e bios but that resulted in a major crash and i had to reformat.. so i figured that was not the right way of "fixing" this anomaly lol...

i'm not too knowledgable on OCing (as you can see from my specs still running at stock settings) but I really want to learn about it and get my hands dirty this summer since i'll have lots of time for reading and all that

for starters i'd like to optimize my ram? something tells me i'm not getting the most out of it at the time being

my system parts are all up to date in my signature.. and i am running the very latest bios revision on my motherboard. i know it's not the best MB for changing settings in though.. alas

if anyone can shed some light on this DDR anomaly I'd appreciate it very much!

thanks in advance!

 

[SynthDude2001]

I'm not sure what memory dividers are available on a motherboard like that, but if you don't have any ones above 200/400MHz available (and you should check to see if you do), the only way to get your RAM to run at its rated speed is to overclock the CPU and use the appropriate divider (for instance, increase HTT speed to 250MHz and leave the divider at DDR400). Also make sure you're running the timings and voltage in spec...setting just the RAM to 500MHz (if that is really what you did) should not crash the system at all unless you were overclocking the CPU at the same time, at a speed/voltage that wasn't stable.

 

[orangat]

Originally posted by: Vesper8
hey everyone.. a few months ago i upgraded my ram and bought 2gb of pcz platinum EB ddr500

i got a decent performance hit from it but i was always bothered by the fact that when my system boots up it detects my memory as DDR400

i once tried to change the 400mhz to 500mhz in my a8n-e bios but that resulted in a major crash and i had to reformat.. so i figured that was not the right way of "fixing" this anomaly lol...

You probably have your memory running at standard pc3200 speed. Just change the divider to 5:4 (standard is 1:1) or it could be an option for 250Mhz memory speed.

If you don't have 5:4(250Mhz), then the bios may be outdated or you do not have a revision E A64 - in which case you have to manually change the cpu generator clock to 250 and set the multiplier appropriately.

 

[m1ldslide1]

Originally posted by: orangat

Originally posted by: Vesper8
hey everyone.. a few months ago i upgraded my ram and bought 2gb of pcz platinum EB ddr500

i got a decent performance hit from it but i was always bothered by the fact that when my system boots up it detects my memory as DDR400

i once tried to change the 400mhz to 500mhz in my a8n-e bios but that resulted in a major crash and i had to reformat.. so i figured that was not the right way of "fixing" this anomaly lol...

You probably have your memory running at standard pc3200 speed. Just change the divider to 5:4 (standard is 1:1) or it could be an option for 250Mhz memory speed.

If you don't have 5:4(250Mhz), then the bios may be outdated or you do not have a revision E A64 - in which case you have to manually change the cpu generator clock to 250 and set the multiplier appropriately.

I don't believe this is right at all. DDR500 memory is rated to run at 250Mhz 1:1, not 5:4. 250Mhz at 5:4 is actually 208Mhz.

To answer the OP, DDR500 is made for overclockers, and it essentially means that your memory is factory-guaranteed to overclock up to 250Mhz 1:1. So if you set your HTT (mem mhz) to 250 (up from 200 stock) then you'll have ddr500. If you have no idea what I'm saying to you, which is OK, then you need to read up on overclocking.

Start here:
http://forums.anandtech.com/messageview...atid=28&threadid=1497607&enterthread=y

Read that about 25 times, and every other overclocking A64 guide you can find and post back with questions. After you understand things like HTT, CPU multiplier, HTT multiplier, memory divider, vdimm and vchip voltages, and memory latencies you'll be ready to start overclocking. Or you could start overclocking before you really understand that stuff, and you might learn faster. Just don't crank up your vchip voltage above 1.55v and you'll be fine.

 

[n7]

As was mentioned, if you have an option in the bios for a RAM divider of 250, that will get your RAM to 244.44 (aka DDR489), close to DDR500.
You may need to manually set the timings to default for 250 though, which could have been why it crashed earlier.

Or, since it seems you aren't OCing & don't wish to, lower the CPU multi to 9x & run 9x250 instead of 11x200. (You'll also need to lower HT multi to 4x aka 800).

That will set your CPU @ 2250 MHz with the RAM @ 250 (DDR500).

 

[m1ldslide1]

n7 - how does a divider of 250 get you DDR489? 250/400 = .625, which multiplied by 200Mhz (stock ddr400 speed) gets you 125Mhz, or DDR250. If you mean .625 * 400, then you get 250, but does that mean the mobos you're used to represent CPU speed as double-pumped? In my experience (3 mobos, so not a ton) it's up to the user to understand that they multiply HTT x2 to get their DDR rating.... I also don't get why simply setting a divider would automatically ratchet the HTT speed up with it. You must have some seriously automated OC features in that a8n32-sli deluxe...

Just looked at the OP's motherboard, and I had the asus a8n-sli which I'm guessing is a very similar BIOS. In my BIOS there was nothing that said "memory divider", instead, you can set your memory speed to ddr400 (default), ddr333, and so on back down. If you set it to ddr333, you're running at 5:4 (4/5 = 333/400 = .8325). If your stock CPU speed is 200Mhz, if you set your memory to ddr333 then you will be running at .8325 x 200, which is 166mhz. If you want to hit 250Mhz with a 5:4 divider you'll actually need to set DDR to 333 and your memory speed to 300Mhz.

If you do like n7 suggested and set your HTT (either called memory speed or CPU speed in the bios - don't remember exactly) to 250mhz and your multi to 9x with no divider, then you will be running at 2250 at ddr500 (250 x 9 @ 1:1 = 2250). This doesn't really get you anything though, as gaming speed is bound by CPU mhz rather than memory bandwidth. That's why you use a divider - to get a higher CPU speed in exchange for less memory bandwidth. It's a great trade-off for gaming, if that's what you're into.

 

[orangat]

Originally posted by: m1ldslide1

Originally posted by: orangat

Originally posted by: Vesper8
hey everyone.. a few months ago i upgraded my ram and bought 2gb of pcz platinum EB ddr500

i got a decent performance hit from it but i was always bothered by the fact that when my system boots up it detects my memory as DDR400

i once tried to change the 400mhz to 500mhz in my a8n-e bios but that resulted in a major crash and i had to reformat.. so i figured that was not the right way of "fixing" this anomaly lol...

You probably have your memory running at standard pc3200 speed. Just change the divider to 5:4 (standard is 1:1) or it could be an option for 250Mhz memory speed.

If you don't have 5:4(250Mhz), then the bios may be outdated or you do not have a revision E A64 - in which case you have to manually change the cpu generator clock to 250 and set the multiplier appropriately.

I don't believe this is right at all. DDR500 memory is rated to run at 250Mhz 1:1, not 5:4. 250Mhz at 5:4 is actually 208Mhz.

To answer the OP, DDR500 is made for overclockers, and it essentially means that your memory is factory-guaranteed to overclock up to 250Mhz 1:1. So if you set your HTT (mem mhz) to 250 (up from 200 stock) then you'll have ddr500. If you have no idea what I'm saying to you, which is OK, then you need to read up on overclocking.

Start here:
http://forums.anandtech.com/messageview...atid=28&threadid=1497607&enterthread=y

Read that about 25 times, and every other overclocking A64 guide you can find and post back with questions. After you understand things like HTT, CPU multiplier, HTT multiplier, memory divider, vdimm and vchip voltages, and memory latencies you'll be ready to start overclocking. Or you could start overclocking before you really understand that stuff, and you might learn faster. Just don't crank up your vchip voltage above 1.55v and you'll be fine.

Well it proves you know less than what you think you know.

The new (rev E) 5:4 divider allows for the use of faster RAM without overclocking the cpu or HT bus.

I don't even want to know how on earth you derived 208Mhz. Now read this a few times and you'll be fine
http://www.anandtech.com/cpuchipsets/showdoc.aspx?i=2469&p=3

 

[SmokeMojo20]

My Neo2 Platinum shows it at DDR400 even though I am OC to 256Mhz which puts the memory at DDR512. Some BIOS don't allow to be set above DDR400 as at the time there was no such thing at DDR500 memory. Some BIOS may also be buggy too. If I use a 183Mhz divider it will show at POST as DDR200. Very wierd. Also if you go above 250Mhz in Neo2 BIOS, the BIOS will show the CPU speed below 100Mhz but changes based on what you set the HTT.

But to get true memory speed use something like CPU-z or RightMark Memory Analizer to check it once you are up and running.

And 5:4 (1.25 over FSB) is not the same as 4:5 (.8 under FSB) --- If you can set to it to 5:4 and leave CPU at stock 200 then 200*1.25=250 or DDR500

 

[n7]

Okay guys...there's some major confusion in this thread on how to calculate RAM dividers.
I too used to think it was simple fractions...but it's not quite that simple.
Here's the way i know of that works for A64 architechture:


How to calculate RAM dividers:

(CPU multi x 200) / RAM divider (i.e. 166) = ___(always round this up if not whole number)

CPU multi x HTT / result of initial calculation = actual RAM speed

e.g.
OCed CPU clockspeed / result of the first calculation = actual RAM speed

one full example:

12 x 200 / 166.66 = 14.4 rounded up -> 15

12 x 220 / 15 = 176 aka DDR352


Let's take the OP's situation.

He has a 11x200 CPU.

So we do 11x200 = 2200.
Divider he wants to use is 250.
So we get 2200/250 = 8.8 rounded up = 9

Therefore, 2200/9 = 244.44 = DDR489, not DDR500

With even multis you can calculate using simple fractions, but with odd multis, it's not the same.
Lets say SmokeMojo20 wants to use the 166 divider with his CPU @ 2304.
9x200 = 1800
1800/166.66 = 10.8 up = 11
2304/11 = 209.45 = DDR419

If SmokeMojo20 were to just calculate by using the incorrect method you guys have been describing, he'd go 256x0.8333 = 213 (DDR426), which isn't what his result would be.

 

[orangat]

Originally posted by: n7
.....

How to calculate RAM dividers:

(CPU multi x 200) / RAM divider (i.e. 166) = ___(always round this up if not whole number)

CPU multi x HTT / result of initial calculation = actual RAM speed

e.g.
OCed CPU clockspeed / result of the first calculation = actual RAM speed

one full example:

12 x 200 / 166.66 = 14.4 rounded up -> 15

12 x 220 / 15 = 176 aka DDR352

................

A more complete equation :-
Memory speed=A64 Speed / ceil(CPU multiplier / Divider)

Divider is RAM/FSB
Ceil is to round fractions up.

So memory speed= 2200 (3700+) / ceil(11 / (5/4))
= 2200 / ceil (8.8)
= 2200 /9 = 244.44

This should be helpful for people (not you n7) who don't understand or don't want to know what HTT/multipliers/dividers actually do.

 

[m1ldslide1]

Well it proves you know less than what you think you know.

OK so now I'm totally confused. I haven't had a motherboard with BIOS option "divider". All I've had is HTT mhz, CPU multi, HT multi, and an option on both my abit and asus boards labelled "DDR". DDR was listed as 266,333,400,433,466,500, and so on. I'm not sure if those numbers are exactly right, but that's the idea. When I'm attempting to OC my 3700, I start off with 200x11 = 2200. I can raise my HTT to 228Mhz without adjusting any other setting, which is 228x11=2508Mhz. When I change that DDR setting I talked about to 333, POST screen lists memory at DDR333 and I'm now able to crank up my HTT to about 273Mhz. Here's why I thought I knew what I was talking about:
333/400 = .8325
4/5 = .8
228 / .8325 = 273

So in other words, I figured the memory divider was running your DDR400 at a lower bandwidth, ddr333, in order to get more CPU cycles out of it. The math hasn't always worked perfectly, especially at the x11 multiplier, but it's worked closely enough that I figured I had it figured out. I posted in the forums a couple of times asking about memory dividers when I was trying to learn and was basically ignored. So I kept playing with it, kept reading zebo and whatever else, and didn't feel like my understanding was contradicted. It's pretty lame that someone would suggest "don't want to know" as I've spent SO many hours trying to figure it out.

I understand the equations from n7 and orangat, but it doesn't seem to do me much good as I don't apparently have a BIOS that supports "memory dividers". Anyone clear this up?

 

[orangat]

Ok.

You probably confused 5:4 with 4:5 - there are new dividers above 1:1 with rev e. My first reply to you has a link which explains them.

Some bios don't show the options to choose dividers like 2:3, 5:6, 1:1, 7:6 etc but show them as 133,166,200,233 etc - same thing.

Feel free to ask if you have more questions.

 

[betasub]

Originally posted by: m1ldslide1
OK so now I'm totally confused. I haven't had a motherboard with BIOS option "divider". All I've had is HTT mhz, CPU multi, HT multi, and an option on both my abit and asus boards labelled "DDR". DDR was listed as 266,333,400,433,466,500, and so on.

Yes, it seems you are total confused. The memory speeds you list not absolute values, but instead are memory dividers (albeit confusing relabeled by Abit in the BIOS). The DDR values 266, 333 etc are in fact ratios of the default DDR400 speed, that is:

BIOS option ---> Divider
266 [ /400 ] 2:3
333 [ /400 ] 5:6
400 [ /400 ] 1:1
433 [ /400 ] 13:12
466 [ /400 ] 7:6
500 [ /400 ] 5:4

Memory divider is applied to the HTT speed you select in BIOS (default 200 or DDR400).

 

[orangat]

Originally posted by: betasub
.......
.......
BIOS option ---> Divider
266 [ /400 ] 2:3
333 [ /400 ] 5:6
400 [ /400 ] 1:1
433 [ /400 ] 13:12
466 [ /400 ] 7:6
500 [ /400 ] 5:4

Memory divider is applied to the HTT speed you select in BIOS (default 200 or DDR400).

It can be misconstrued as the memory deriving its speed from the HTT and divider which is not correct. The ram:htt ratio is just easier to understand but memory speeds are derived from the cpu clock and divided down.

 

[n7]

Originally posted by: orangat
A more complete equation :-
Memory speed=A64 Speed / ceil(CPU multiplier / Divider)

Divider is RAM/FSB
Ceil is to round fractions up.

So memory speed= 2200 (3700+) / ceil(11 / (5/4))
= 2200 / ceil (8.8)
= 2200 /9 = 244.44

This should be helpful for people (not you n7) who don't understand or don't want to know what HTT/multipliers/dividers actually do.

Yeah, copied from XS ?

I did the same, but i paraphased it my way, since i find the original quote from XS a tad confusing


Thanx to this thead, i got thinking about my own overclock, & realized i could use the 8.5 CPU multi (omg yes, the dreaded half multi) to my advantage.

I was running 9x289 (2601 MHz) with 133 divider (DDR372).
Now i am running 8.5x306 (2601 MHz) with 133 divider (DDR400)
So this thread indirectly helped out, since i'd always avoided the half multis till today

 

[TheRyuu]

I got the same RAM as OP and although this is a bit OT, it's nice RAM. For some reason, it loves 2.6v (lowest mobo can set it) at DDR500 @ 3-3-2-7. Maby i can make the timings a little bit tighter, but I don't have the time right now.

Just set the FSB (aka HTT) to 250mhz and have the RAM in 1:1 (aka 200mhz/DDR400). Then just set the multiplyer to whatever will bring you to the correct mhz speed of your processor, and make the K8 to NB a 4x multiplyer instead of a 5x. That should get your ram in 1:1 @ 250mhz. You might have to raise the voltage of the processor a little be because of the raise in the HTT speed, but only by a little since your running it at basically the same speed in the end.

 

[orangat]

Originally posted by: n7

Originally posted by: orangat
A more complete equation :-
Memory speed=A64 Speed / ceil(CPU multiplier / Divider)

Divider is RAM/FSB
Ceil is to round fractions up.

So memory speed= 2200 (3700+) / ceil(11 / (5/4))
= 2200 / ceil (8.8)
= 2200 /9 = 244.44

This should be helpful for people (not you n7) who don't understand or don't want to know what HTT/multipliers/dividers actually do.

Yeah, copied from XS ?

I did the same, but i paraphased it my way, since i find the original quote from XS a tad confusing

Thanx to this thead, i got thinking about my own overclock, & realized i could use the 8.5 CPU multi (omg yes, the dreaded half multi) to my advantage.

I was running 9x289 (2601 MHz) with 133 divider (DDR372).
Now i am running 8.5x306 (2601 MHz) with 133 divider (DDR400)
So this thread indirectly helped out, since i'd always avoided the half multis till today

Speak for yourself. I don't know what XS is. The AT link I posted earlier had all the information I need.

 

[m1ldslide1]

Originally posted by: betasub

Originally posted by: m1ldslide1
OK so now I'm totally confused. I haven't had a motherboard with BIOS option "divider". All I've had is HTT mhz, CPU multi, HT multi, and an option on both my abit and asus boards labelled "DDR". DDR was listed as 266,333,400,433,466,500, and so on.

Yes, it seems you are total confused. The memory speeds you list not absolute values, but instead are memory dividers (albeit confusing relabeled by Abit in the BIOS). The DDR values 266, 333 etc are in fact ratios of the default DDR400 speed, that is:

BIOS option ---> Divider
266 [ /400 ] 2:3
333 [ /400 ] 5:6
400 [ /400 ] 1:1
433 [ /400 ] 13:12
466 [ /400 ] 7:6
500 [ /400 ] 5:4

Memory divider is applied to the HTT speed you select in BIOS (default 200 or DDR400).

Thanks for the input everybody. It's weird how when you think you understand something a certain way, new information can kind of conform itself to that understanding even though it isn't necessarily so. I'm looking forward to reexamining my OC now to see if I can get some more out of it.