# AMD APU with 1600mhz or 1866mhz?



## camoxiong (Jul 9, 2012)

Which well be better with an AMD APU CPU and what is the differences between those 2 RAM Speed with the APU?


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## CDdude55 (Jul 9, 2012)

Memory speed makes little difference for most software, so there is not much difference in the grand scheme of things. Amount of memory is generally more important then it's speed or timings.


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## camoxiong (Jul 9, 2012)

I mean the AMD APU, will it make any differences with the APU with the 1866mhz ram?


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## CDdude55 (Jul 9, 2012)

camoxiong said:


> I mean the AMD APU, will it make any differences with the APU with the 1866mhz ram?



The AMD A4 APU's support up to 1600mhz (but it will still boot with 1866mhz memory, just running at 1600mhz, but that makes little difference as mentioned) the A6 and A8 line of APUs support 1866mhz natively meaning it should boot at those speeds.

http://www.amd.com/us/products/desk...s/Pages/a-series-model-number-comparison.aspx

Everything should work fine.


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## seronx (Jul 9, 2012)

Go with 1866...
G.SKILL Ripjaws X Series 8GB (2 x 4GB) 240-Pin DDR...

You can only have two slots filled with 1866 MHz without going into the "OC" spec

G.SKILL Ripjaws X Series 8GB (2 x 4GB) 240-Pin DDR... <-- comparing to this

8 ÷ 1866 -> 4.28 ns
7 ÷ 1600 -> 4.375 ns

Also it is $5 cheaper...then you have 29.9 GB/s of bandwidth with DDR3-1866 and 25.6 GB/s with DDR3-1600.


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## DarkOCean (Jul 9, 2012)

For an apu i would choose any day frequency over latency.
See this http://www.techpowerup.com/reviews/AMD/A8-3850_Fusion_GPU_Performance/14.html


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## devguy (Jul 9, 2012)

If you're using the APU graphics and not a dedicated graphics card, and you are wanting to do things using the GPU (like games and stuff), then faster memory is worth it.

For CPU benchmarks, you'd be unlikely to see much of a difference at all between ddr3 1066 and ddr3 1866.


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## seronx (Jul 9, 2012)

devguy said:


> For CPU benchmarks, you'd be unlikely to see much of a difference at all between ddr3 1066 and ddr3 1866.


It depends on the application.










Most of the time for the CPU it isn't the RAM speed that is lowering performance but the HDD speed.

HDD -> RAM

HDD latency -> ~10 ms to ~20 ms (10,000 ns)
RAM Latency -> ~4 ns to ~6 ns
Slowest SSD -> ~0.5 ms (Most ssds you can get now are in the ~0.01x range which is about ~1x ns)

If the memory benchmark has to read the HDD/SSD first those devices are going to be a bottleneck and make the RAM speeds with different cas latencies perform the same regardless.


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## camoxiong (Jul 10, 2012)

Well, I want a a8 3780k with a r6770 in dual graphics mode. What well be better 1866mhz or 1600mhz?


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## slyfox2151 (Jul 10, 2012)

Neither... or either....


there will be no difference.


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## CaptainFailcon (Jul 10, 2012)

slyfox2151 said:


> Neither... or either....
> 
> 
> there will be no difference.



WRONG
the APU relies heavily on memory bandwidth for graphics the faster/tighter timings the better


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## HossHuge (Jul 10, 2012)

camoxiong said:


> Well, I want a a8 3780k with a r6770 in dual graphics mode. What well be better 1866mhz or 1600mhz?



I hope you mean a HD 6670 cause you can't run a hd 6770 in dual mode with an apu.


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## CaptainFailcon (Jul 10, 2012)

HossHuge said:


> I hope you mean a HD 6670 cause you can't run a hd 6770 in dual mode with an apu.



a single 6770 will be faster


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## Zen_ (Jul 10, 2012)

Everything I've read indicates that there is a tangible benefit using faster memory. Even on my A4-3400 with the gimped graphics, there is a noticeable improvement running 1600 MHz memory @ 1866 with looser timings. 

I would caution you away from trying an APU + add in card though. The A-series APU's are an awesome value if the integrated graphics are enough, but add in cards sorta defeat the value. Unless the system listed in your profile is sold or not working, just buying a 5770 or GTX 460 for under $90 will be a lot faster than an A8-3870k + 6670 in the hybrid crossfire mode, without the usual scaling limitations and quirks of crossfire.


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## baggpipes (Jul 10, 2012)

HossHuge said:


> I hope you mean a HD 6670 cause you can't run a hd 6770 in dual mode with an apu.



he right dont get that 6770 for that setup get the 6670... But i would do this, get a 6850 or 7770 for ur comp now... then upgrade ur cpu when piledriver hits... and skip APUs...


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## camoxiong (Jul 10, 2012)

HossHuge said:


> I hope you mean a HD 6670 cause you can't run a hd 6770 in dual mode with an apu.





CaptainFailcon said:


> a single 6770 will be faster





baggpipes said:


> he right dont get that 6770 for that setup get the 6670... But i would do this, get a 6850 or 7770 for ur comp now... then upgrade ur cpu when piledriver hits... and skip APUs...



Oh shoot, I forgot, I mean the 6670. My bad. I was tired and I typed the wrong card.


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## Aquinus (Jul 10, 2012)

The faster the memory the more the iGPU on the APU will benefit from it, but only to a point with certain games.

I think you were looking for this.


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## pantherx12 (Jul 10, 2012)

The faster the memory the better.

You'll need fast ram whilst playing games since your video memory will be there as well as usual memory etc.


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## camoxiong (Jul 11, 2012)

ok, now i get it. because Anquinus link the comparison chart


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## slyfox2151 (Jul 12, 2012)

CaptainFailcon said:


> WRONG
> the APU relies heavily on memory bandwidth for graphics the faster/tighter timings the better



it doesn't matter since hes not using the APU.


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## Aquinus (Jul 12, 2012)

slyfox2151 said:


> it doesn't matter since hes not using the APU.





camoxiong said:


> Which well be better with an AMD APU CPU and what is the differences between those 2 RAM Speed with the APU?



He asked a question, it doesn't mean he needs the hardware for us to answer it.


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## camoxiong (Jul 15, 2012)

Aquinus said:


> He asked a question, it doesn't mean he needs the hardware for us to answer it.



Yeah, because my next build is an apu build on a budget


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