Memory Scaling on Core i7 - Is DDR3-1066 Really the Best Choice?
by Gary Key on June 24, 2009 9:00 AM EST- Posted in
- Memory
Memory Pricing
We remember paying over $600 for 2GB of DDR3-1600 C7 rated at 1.90V almost two years ago. About nine months ago, when Core i7 launched a DDR3-1600 C7 6GB 1.65V kit cost us $415. A DDR3-1600 C7 1.65V 6GB kit cost us $140 last week. To add insult to injury, a recently purchased DDR3-1600 C9 1.65V 6GB kit set us back $86 compared to the $195 we paid four months ago. To say things have changed in the DDR3 memory market over the past two years would be an understatement.
In today’s testing, we did our best to utilize retail kits from various manufacturers based on their stock speed and timing ratings for each of our memory settings. We felt this was a better choice than taking a DDR3-2000 kit and using it at different speeds and timings as that would not represent what the actual product for sale at these price points are capable of in our test system. Of course, we violated this principal twice but for good reason. There are not any 1066 C5 kits so we bumped the voltage slightly on the Patriot 1066 C7 kit to run at these timings. Our 1866 C7 kit became incapacitated and we switched to a 2000 C8 kit that actually cost less and performed better.
The price levels listed represent our cost from Newegg at the time of purchase. Of course, prices for 6GB kits vary widely depending on the manufacturer, rebates, specifications, and product availability so consider these prices to represent a current aggregate average. We fully realize that purchasing a DDR3-2000 CAS8 kit for $235 that is capable of running DDR3-1866 C7 at like voltages is usually a better value than a $289 1866 C7 kit. Kit prices range from $80 for the DDR3-1066 C7 kit up to the $260 DDR3-2000 C8 modules for this article.
Our lead off contestant is the Patriot DDR3-1066 C7 PSD36G1066KH 6GB kit that we utilized for both the 1066 C7 and C5 results. This memory kit only required 1.60V for CAS5 operation and comes in at the low price of $80. For those operating on a strict budget, we cannot say enough good things about this kit as it easily reached DDR3-1600 C9 on 1.65V and 1.225V VTT. Speaking of DDR3-1600 C9 kits, we are now seeing these 6GB kits below $90 and if they arrive with the right IC/PCB combination, they could potentially make a great kit for down clocking to 1333 C6, which is one of our sweet spot settings for overall performance on this platform.
We tapped Corsair for our DDR3-1333 C9 kit, SuperTalent for the DDR3-1333 C8 modules, and GEIL for our DDR3-1333 C7/C6 kits. We turned to Patriot once again for DDR3-1600 C9, OCZ for a really great DDR3-1600 C8 setup, Corsair for DDR3-1600 C7, and Mushkin for one sweet DDR3-1600 C6 package. We utilized GSkill’s DDR3-2000 C8 kit for our DDR3-1866 C7 and limited overclock results. We will be reviewing each kit utilized shortly (and others) to determine the overall best value based on clocking abilities, technical support, warranty, and cost.
Memory Designations –
One of the more confusing aspects of selecting DDR3 memory are the two common designations, which are both technically wrong. The first commonly used term describes the theoretical bandwidth, as in PC16000. This numbering system represents the peak transfer rate in MB/s of the module. The other common designation describes the effective clock speed in terms like 2000MHz. If the product description does not contain the effective clock speed and you only see a number like PC8500, then divide it by eight. Therefore, through the magic of math and marketing, PC8500 becomes 1066MHz.
Of course, this is not the actual clock speed, but rather the data rate. In other words, while PC8500 sounds extremely impressive and 1066MHz just a little less so, the actual operating frequency of the DDR3 devices is much less. There is a history on why we have these inflated numbers as it dates back to the time of RAMBUS, but that is a story for another article. We just wish that the memory suppliers would pick one designation and go with it. In the meantime, we will report our numbers today in effective data rate for simplicity state. We will refer to DDR3-1066 5-5-5-18 as simply 1066 C5 as an example.
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ilkhan - Wednesday, June 24, 2009 - link
running a small cross section of the tests in dual channel mode would be the improvement I can see. Awesome article.Gary Key - Wednesday, June 24, 2009 - link
We will have dual channel results in the 3GB, 4GB, 6GB, 12GB article in a couple of weeks. Right now, you are not giving up that much if any at all in most of these apps with a dual channel 4GB/8GB setup.The0ne - Wednesday, June 24, 2009 - link
The use of percentages and the comments made for them is vastly different than comments made for video cards. A 14% gain in minimal FPS isn’t much, especially for Dawn of War II. To state the game is a “stutter fest” from a low of 12FPS to “smooth” of a high 17FPS is really exaggerating the picture. 17FPS is still a “stutter fest.”From the data collected it really can be said, much like video card reviews is, that if you have the money and want the best then buy the faster memory, otherwise it is a waste of your hard earn money. My point of posting this comment is that the objectivity should not be any different when talking about FPS gains. Here it appears to sound more pleasing even though the numbers don’t show much gain at all.
GourdFreeMan - Thursday, June 25, 2009 - link
For nearly all human beings the perception of motion as opposed to a progression of still frames lies in the 8-20 fps range. It is not beyond the realm of possibility that Gary's perception of stutter is from crossing this threshold at least momentarily while playing Dawn of War II. Of course, you could probably more cheaply improve your minimum frame rate by buying a better video card than faster RAM unless the game really is (CPU) memory bound.SiliconDoc - Sunday, July 5, 2009 - link
I kind of thought the opposite of the two prior comment (except I agree it may have been exagerrated to go with smooth as silk)- it seems to me that 2%-5%-7%-14% framerate gains are usually considered quite impressive and quite a win in videocard comparisons, and especially in minimum framerate areas, that would be quite nice.I understand it's a different review person, hence perspective and emphasis to a large degree, but it impressed me in the sense that those sized percentages are the end all and be all in video card comparisons - oh golly the declatory winners with that kind of spread based on just videocard performance... so discounting it here - no way.
So, except for the statement that overclocking the cpu is as much or more a gain and overpowers and negates ram timings to a degree (if I caught that latter part intent correctly in the article), I'd have to say the ram advantage is very important to the hardcore videocard shoppers - it can really add quite an edge - as much as a videocard / head to head choice based on benches. Maybe enough to wait for higher clocked ram prices to drop, or score that great deal on overclockable ram.
I enjoyed the article mainly because of those FPS benches shown.
fishbits - Wednesday, June 24, 2009 - link
"Of course, those that are doing all of these activities and more will benefit from purchasing fast low-latency memory and we even suggest getting 12GB while you are at it."How much of a performance hit (if any) is there typically in populating 6 banks on an i7 system versus 3?
bh192012 - Wednesday, June 24, 2009 - link
I'm not sure I understand the conclusion. You recommend DDR3-1333 C6 for people who want a little more speed, but it seems to me that your data shows that DDR3-1600 C9 is faster and cheaper?Example:
1066 c5 / min fps H.A.W.X. 80/50 = 1.60$ per frame
1333 c6 / min fps H.A.W.X. 125/52 = 2.40$ per frame
1600 c9 / min fps H.A.W.X. 85/54 = 1.58$ per frame (winner)
1600 c6 / min fps H.A.W.X. 175/56 = 3.13$ per frame
QChronoD - Wednesday, June 24, 2009 - link
I would have to assume that you are doing your calculations on the Min frame rate?Personally, I would look at that and see that they are about equal at the minimum, but 1333c6 is almost 50% faster on average!
I'd suggest redoing your $/fps with the average rates.
bh192012 - Wednesday, June 24, 2009 - link
Where is 1333 c6 50% faster than 1600 c9? I think you have confused the price chart with a benchmark or something. Also, min FPS are more important.Affectionate-Bed-980 - Wednesday, June 24, 2009 - link
Uhh obviously no one read this article really because Page 11 is supposed to be about choosing a kit, yet it has 3D rendering benchmarks which should be on page 12.... Yeah..