Radeon HD 8670 showing lower memory clock and bandwidth.

[tusharkant15]

Hi! This is my first post on Anandtech forums so pardon me if it's a little weired.

I recently purchased an AMD A10 6800K along with an MSI FM2 A55 E33 motherboard and 8GB 1600Mhz ram. I haven't overclocked the CPU at all but have overclocked the GPU to 1013 (844 default). The problem is that the Catalyst Control Center shows that the memory frequency of the GPU is 800MHz and the bandwidth is 12.8 GBytes/s which is lower than the information I found on the internet.

Does anyone else have the same APU/Mobo and can confirm that that they too get similar results or is it just me?

 

[KingFatty]

I don't have specific experience, but there are 2 factors to consider: 1) is the computer dynamically adjusting its settings to save power while you check the speeds? I know my discrete video card does that, and shows a very low score in Catalyst Control Center, so maybe yours is doing a similar function, so maybe try running a 3D application/game in a window while you monitor the speeds to see if they rise to full speed; and 2) is the catalyst control center fully accurate? Maybe there is a bug or issue where it's mis-reporting, and you can try a different utility to monitor the speeds. In fact, you can get utilities that record a chart of the speeds over time, and see how they fluctuate depending on load.

 

[Durvelle27]

the reason your memory clock is lower is because it uses the system RAM and that's what the system ram is set to. If you want a higher memory clock and bandwidth then you will have to OC the RAM.

1866 RAM = 933MHz
2133 RAM = 1066MHz

 

[Enigmoid]

Hi! This is my first post on Anandtech forums so pardon me if it's a little weired.

I recently purchased an AMD A10 6800K along with an MSI FM2 A55 E33 motherboard and 8GB 1600Mhz ram. I haven't overclocked the CPU at all but have overclocked the GPU to 1013 (844 default). The problem is that the Catalyst Control Center shows that the memory frequency of the GPU is 800MHz and the bandwidth is 12.8 GBytes/s which is lower than the information I found on the internet.

Does anyone else have the same APU/Mobo and can confirm that that they too get similar results or is it just me?

You have two RAM sticks right?

 

[tusharkant15]

That makes sense. Thanks! I was thinking it's the motherboard.

 

[tusharkant15]

No I have 1 8GB stick...I did this to give room for a ram upgrade in the future but I guess I'll have to replace it with a faster one instead...if only I hadn't been so cheap and gone with the 2400Mhz 4GB stick instead(it was only Rs 100 more expensive :$)

 

[SlowSpyder]

No I have 1 8GB stick...I did this to give room for a ram upgrade in the future but I guess I'll have to replace it with a faster one instead...if only I hadn't been so cheap and gone with the 2400Mhz 4GB stick instead(it was only Rs 100 more expensive :$)

Since you're using one stick of memory you're only getting single channel speeds. Add another 8GB, or get two 4GB sticks of the same speed and you'll double your bandwidth. I think the A10 6800k supports faster memory, too.

 

[ElFenix]

adding another 8 GB stick would double your memory bandwidth.

as durvelle explained, 1600 is actually the megatransfers (MT), rather than the MHz. the ram transmits data on both the rising and falling edges of the frequency, so 1600 actually runs 800 MHz. even that 800 MHz is quadruple the actual clock, so the clock is 200 MHz. it can transfer 64 bits of data per transfer, which is 8 bytes. 1.6 gigatransfers/sec * 8 = 12.8 gigabytes per second. adding another stick will boost you up to 25.6 gigabytes per second peak.

 

[Concillian]

Going for the extremely high speeds is questionable value, but you can get decent 2133 memory for pretty reasonable prices (at least around here or if you can find someone who will ship internationally).

2133 CAS10 memory isn't too expensive.

Here's what you need:
2 sticks... this is the most important. 2 sticks = double bandwidth since the CPU supports dual channel.
speed ... obviously speed = more bandwidth. Speed costs money, so go with bang for the buck. CAS10 DDR3-2133 is generally only marginally more expensive than CAS9 DDR3-1600, but higher can cost a lot more.
Last worry about CAS latency. It plays a role, but overall it's a smaller role than bandwidth for the graphics performance. Even if you need to drop all the way down to CAS 12 or 13, speed is more important.

Those are your priorities.

 

[Durvelle27]

Just for reference

As you can see it does benefit greatly from faster RAM

 

[Enigmoid]

If you are going to game put in two sticks or you will lose half your performance. No point to OC on one stick.

 

[SPBHM]

going for a single stick with an APU is one of the worst things you can do... 2x2GB would have been A LOT better for gaming.

 

[tusharkant15]

Thanks! I wasn't aware that two sticks is better than one. I guess I'll get a cheap 4Gb 1600 ram for now and upgrade to 2133 later (2133 seems to be the max for the apu).

Will this work or will it be best to get another 8 Gigs?

 

[Enigmoid]

Thanks! I wasn't aware that two sticks is better than one. I guess I'll get a cheap 4Gb 1600 ram for now and upgrade to 2133 later (2133 seems to be the max for the apu).

Will this work or will it be best to get another 8 Gigs?

You need the same speed across the two sticks for it to really work.

Different capacity sticks may also have problems.

 

[Durvelle27]

Thanks! I wasn't aware that two sticks is better than one. I guess I'll get a cheap 4Gb 1600 ram for now and upgrade to 2133 later (2133 seems to be the max for the apu).

Will this work or will it be best to get another 8 Gigs?

The sticks have to be the same size and same speed or they will run in single channel

 

[SPBHM]

The sticks have to be the same size and same speed or they will run in single channel

are you sure? since 2003 or so Intel supports dual channel with different amount of memory per channel (like 4+8 would run with 8GB in dual and 4 in single more or less),

I remember some llano laptops doing the same, with 6GB (2+4), with the IGP using memory from the dual channel portion, and the performance difference from that mode and pure dual channel was minimal, but compared to pure single channel it was huge, I would expect Trinity/Richland to do the same?

 

[Enigmoid]

are you sure? since 2003 or so Intel supports dual channel with different amount of memory per channel (like 4+8 would run with 8GB in dual and 4 in single more or less),

I remember some llano laptops doing the same, with 6GB (2+4), with the IGP using memory from the dual channel portion, and the performance difference from that mode and pure dual channel was minimal, but compared to pure single channel it was huge, I would expect Trinity/Richland to do the same?

I believe that the system does some sort of hybrid Dual channel, possibly splitting the larger stick into two sections (ie a 4 GB stick and an 8 GB stick will be seen as a 4 GB stick and two 4 GB sections of the 8 GB stick, one of which will work in pseudo dual mode.

It will perform better than single channel but not quite as good as dual channel (closer to dual channel than singlechannel).