What kind of performance increases does Kaby Lake quads get from dual channel ram?

[TurtleCrusher]

Hello everyone,

My system only has one 8GB stick of DDR4 in it. I was wondering if I'm not using it for 3d gaming does dual channel help out?

Also, I'm thinking of adding in a 4GB DDR4 stick to stave me off until a 16GB stick becomes relatively affordable. It still runs in dual channel with mismatched sized ram, right?

Thanks

 

[epsilon84]

Happy to run some quick benchmarks on my 6700K if you want, what kind of work do you do on your PC?

 

[TurtleCrusher]

I'm just using it for gaming (new and old, including Dolphin), photo editing, and browsing, while also streaming to Chromecast sparingly.

Offering to bench it is a lot more than I expected, but if you're able to that it would be appreciated.

 

[IntelUser2000]

I'm just using it for gaming (new and old, including Dolphin), photo editing, and browsing, while also streaming to Chromecast sparingly.

Offering to bench it is a lot more than I expected, but if you're able to that it would be appreciated.

Back in the Pentium III days, benchmarks indicated a ~5% increase from 33% increase in bandwidth. Looks like its similar with Skylake/Kabylake.

Here's a Techspot testing of DDR4-2133 to DDR4-4000 on a Skylake 4.5GHz chip.

https://www.techspot.com/article/1171-ddr4-4000-mhz-performance/page2.html

It shows quite a nice gain on the set of tests they have done. Mind you, the differences between dual and single channel memory would be larger than the difference between DDR4-2133 and DDR4-4000. You can keep identical timings between dual and single channel, while you can't with DDR4-4000. With some platforms, you can observe weird behaviors on your system with single channel memory. The Apollo Lake mini systems sometimes become stuttery with single channel, while its fluid with dual, even though some system benchmarks may not indicate it.

I'm going to guess:
-Browsing/light tasks: 10-15%
-Gaming: 15-25%
-Photo editing: 15-25%

 

[ZGR]

Don't skimp out on slow DDR!

 

[pantsaregood]

What kind of performance increases does Kaby Lake quads get from dual channel ram?

About $3.50.

 

[TurtleCrusher]

Back in the Pentium III days, benchmarks indicated a ~5% increase from 33% increase in bandwidth. Looks like its similar with Skylake/Kabylake.

Here's a Techspot testing of DDR4-2133 to DDR4-4000 on a Skylake 4.5GHz chip.

https://www.techspot.com/article/1171-ddr4-4000-mhz-performance/page2.html

It shows quite a nice gain on the set of tests they have done. Mind you, the differences between dual and single channel memory would be larger than the difference between DDR4-2133 and DDR4-4000. You can keep identical timings between dual and single channel, while you can't with DDR4-4000. With some platforms, you can observe weird behaviors on your system with single channel memory. The Apollo Lake mini systems sometimes become stuttery with single channel, while its fluid with dual, even though some system benchmarks may not indicate it.

I'm going to guess:
-Browsing/light tasks: 10-15%
-Gaming: 15-25%
-Photo editing: 15-25%

A 15-25% bump in CPU perf in gaming would be great. Just ordered a 4GB stick to run in dual channel mode. Thanks.

Don't skimp out on slow DDR!

The existing stick is DDR4 2400, so I bought another stick of the same speed. Looking on Crucial's stie the max they allow is DDR4 2666, so am I really missing out?

About $3.50.

Helpful.

 

[Pick2]

If you have one 8 GB stick , you'll need another 8 GB stick to run in Dual channel , IIRC

 

[TurtleCrusher]

After spending time crawling the web I found Intel's flex memory mode.

Flex mode

This mode results in both dual and single-channel operation across the whole of DRAM memory. The figure shows a flex mode configuration using two DIMMs. The operation is as follows:

• The 2 GB DIMM in slot 1 and the lower 2 GB of the DIMM in slot 2 operate together in dual-channel mode.
• The remaining (upper) 2 GB of the DIMM in slot 2 operates in single-channel mode.

So two thirds of the performance gains of dual-channel in worst case scenario is realized with mismatched ram sizes like this. Hopefully less if its aware which 8gb to use until going over 8gb.

 

[mikeymikec]

OP, are you talking about the laptop in your sig?

How similar are the mobile parts to the desktop ones?

 

[LTC8K6]

Intel has had Flex mode for ram for a long time. You don't have to match module sizes.

 

[Pick2]

Intel has had Flex mode for ram for a long time. You don't have to match module sizes.

Learn something new every day ! The only Intel CPUs I have are in a pair of iMacs