Will expensive ram give me more performance than cheap ram?

[JoostinOnline]

1 minute ago, stconquest said:

I am assuming the kit you replaced the original set with was a dual channel kit?  It crossed my mind earlier, but I figured you probably would have accounted for that.  If you went from two sticks to a single stick, there would be a loss of bandwidth.

I went from 2x4GB to 2x8GB.

[stconquest]

12 minutes ago, JoostinOnline said:

I went from 2x4GB to 2x8GB.

Back to the training thing.  If the system detected the new kit, it might have loosened the timings in order to assure the RAM would be stable.  Over time it would train the RAM through the booting process.  Fast boot apparently is worse at getting the RAM to optimize.  Again, shot in the dark...a.k.a. talking out ma butt... sorta.

 

Magetank referred to "whitesheets".  Some companies (Sansung and Hynix) actually release the optimal settings for particular kits.  I am assuming it is probably detailed as to how to get the most out of each RAM kit; all kinds of timings I probably have to google to learn the definition of.

 

Oh,and training does not yield that much performance.  So if it was really noticeable, it was probably something else.

[JoostinOnline]

1 minute ago, stconquest said:

Magetank referred to "whitesheets".  Some companies (Sansung and Hynix) actually release the optimal settings for particular kits.  I am assuming it is probably detailed as to how to get the most out of each RAM kit; all kinds of timings I probably have to google to learn the definition of.

Well I'd buy a bunch of new RAM to test all this out, but my Scrooge McDuck vault of gold coins is getting a little low.

[MageTank]

11 hours ago, JoostinOnline said:

This was probably 3 years ago, but it was big enough that I immediately noticed it.  I just didn't understand how there could be such a large difference, especially when increasing the capacity.  Like I said, I swapped the RAM back and forth several times to make sure I wasn't imagining it.

 

This Christmas I upgraded to this set (which was much cheaper at the time BTW), and I didn't notice any performance changes, other than SuperFetch working for apps that I haven't opened in a longer point in time.

This is actually very easy to explain. For DDR3, most 4gb sticks are single rank, while most 8gb+ sticks are almost always dual rank. Upon going from single rank to dual rank, you unlock a completely different set of tertiary timings that your IMC must account for, with the nomenclature of "_DR" at the end of their name. Take tRDRD for example, a tertiary timing that benefits read bandwidth. You will see this same timing a few times, with different suffixes (DR, DD, etc). DD is a DPC timing, or DIMMS Per Channel. This timing only activates once you have more than one dimm per channel. On cheap laptops with only 2 SODIMM slots, this timing will have no impact at all on performance. This timing only activates once 2 or more dimms per channel is installed. 

 

Since you likely went from a single rank kit, to a dual rank kit, your IMC recognized that, and had to train these new DR timings. It likely put additional stress on it, so it had to train the rest of the tertiary timings lower to compensate. That being said, it's a fair trade to make for Rank Interleaving, which is a pretty huge advantage when it comes to overall memory performance. Being able to write to one rank while reading from another is pretty serious, and will aid in latency quite a bit. It's a shame companies often lock down laptop BIOS's and prevent us from tinkering with these timings. That's why whenever I buy a laptop, it's going to be the EVGA SC15, since they have every single overclock option unlocked in their BIOS. 

[aithos]

On 1/16/2017 at 9:25 AM, Cantaloupeman said:

https://pcpartpicker.com/list/tv2P7h So this is my build that id like to put together. I will most likely put in an rx480 or something around that performance. The ram however sort of caught me up. The good 3000mhz ram 8gb from corsair is the cheapest 8gb 3000mhz ram available. But it's 60$. Could i just get generic 8gb ddr4 and call it good? Or does ram speed really make a difference?

It depends. 

 

First of all, when you say "faster" RAM are you referring to say 1600vs3200?  If so one of the factors is going to be the MB you choose and whether that chipset can take advantage of the faster speed RAM, often when you look at RAM it is "certified" for speeds above what the motherboard will default it to.  Meaning that you actually need to overclock the RAM to reach it's advertised speeds. 

 

Second, the timing of the RAM is just as important as the speed.  If you have memory where the speed is higher but there is more latency then you need to calculate the "absolute" latency to see if you actually get a performance gain.  So it is very possible to have some slower RAM with better timings and end up with equal or even better performance than something faster, but generally the higher the number the better for speed and the lower the better for things like CAS latency. 

 

Third, one of the things you're paying for with a brand like Corsair is quality control.  I've never had a bad dimm from Corsair (or any major brand) but I've gotten several "house" brands that came bad.  So keep that in mind, if you go with a generic brand there is a higher chance of having issues.  Not to mention: $60 for ram is pretty cheap, there is no way I'd be buying off-brand RAM when you're probably only talking a $20~ dollar difference between the two choices.

 

 

[Nup]

Great thread . have been wanting to read on this (ram speeds etc) for a while.