Memory kit value rating

As we did with previous our memory roundups, in the end you're faced with the question: "how much value do I get for my money". For this we have been using TTR's UMPR rating, and in the next paragraph we'll reiterate what it stands for.

The UMPR rating originates from The Tech Repository, where Kris and Tony introduced a new rating system for memory, which they called Universal Memory Performance Rating, or UMPR in short. The UMPR rating was introduced in this article, which contains a lot of other useful thoughts and information as well. After discussing things a little with the author, I decided to "give it a go" as a rating for our articles.

Before we get started with the rating, all the overclocking results once more in one table. Please notice the voltages at which the maximum overclocks have been reached:



Time for the rating now: how does it work? To put the UMPR rating in English, what Kris and Tony wanted to do is give every ram stick a rating, depending on voltage and cas latency. For the cas latency, they didn't just use the cas rating, but used the real calculated latency. This way, they were hoping to find a fixed number for a memory kit which spanned all cas latencies. For example : a kit which has a cas latency of 7 at 1333Mhz, usually has a cas of 8 at 1600 and 9 at 1800Mhz. If you calculate UMPR for these three values, the results are about the same. Therefore, a memory kit with a cas latency of 7 at 1333Mhz is about equal to a kit of 1600Mhz with cas 8 (not counting the voltages). Second in the equation is the voltage: the lower the voltage a memory kit operates at, the more headroom is expected out of it. For example, a memory kit which performs with a cas of 7 cycles at 1333Mhz at 1.5 Volts, is superior to a memory kit that needs 1.65 Volts to reach the same 1333Mhz at cas 7.

The equation TTR came up with is available in the thumbnail below.


Image (and its contents) courtesy of TheTechRepository.com (click for larger version)

Why is UMPR so important now? Well, when you look for memory in your local shop, you will probably be looking for memory with a certain speed grade (PC8500/PC10600/PC12800/...) and perhaps a certain cas ratio. The UMPR rating now gives you a way to compare the different memory kits that are for sale, the only extra variable you need is the voltage. Now you can decide which one is better: the PC10600C7 @ 1.5V or the PC12800C9 @ 1.65V...

Lately things have become a little more complicated though. Because Intel decided to design a cpu that is capable of handling voltage only up to 1.65v vDimm, memory manufacturers have been forced to change their chip designs to more low voltage models. The result of this is that almost every memory kit now is designed to perform in the window between 1.5V and 1.65V, but is not designed to scale beyond this point. Some memory kits on the market already have internal restrictions that prevent them from scaling beyond 1.65V, as there's an over voltage protection on them. This way, the voltage part in the UMPR equation has lost much of its value, though not all, because there still are many kits out there that do scale well with additional voltage, just remember that not all do.

For further reading, please visit their article which gives an in depth explanation of UMPR, and other Overclocking goodies...

If we use the above formula, this is what our new table looks like :



In this table, I have highlighted the kits with the best UMPR rating in bold. Every kit has a different UMPR rating for every cas latency, and for the average "profile" of mixed cas settings. You could say that the best kit in the average column is the best "overall" memory kit available, when you're not looking for a certain cas ratio. What's most important though is the fact that you see now that every kit has its "specialty" : some are better at cas 7, others at cas 9.

---

Finally, let's have a look at the value these memory kits bring to the table. As prices tend to differ quite a lot between the US and Europe, we made two tables, one for each continent. The US prices were gathered using Froogle.com and Newegg.com, the EU prices were gathered using Tweakers.net Pricewatch and Geizhals.eu.

First up is the USA, with prices in US dollars ($) :



I highlighted the best value kits in this overview. The best overall kit for the US is the OCZ Platinum kit, the second are the Patriot and Geil kits. When you take into account the rebates (R in the table) that are on offer right now, things might change. In this cast the Patriot currently has a $30 rebate from Newegg bringing the price down to an incredible $79,99 including shipping (US). The OCZ also has a rebate of $20, giving it almost equal value. Please remember that these things change over time, and next week any other of these kits can be most valuable depending on the fluctuation of prices and rebates.

A similar table for European customers:



The results are similar to the US results, and the OCZ currently runs away with best value here too. The value you get for less than €100 is enormous, my feeling is however that the OCZ might be approaching EOL (End-of-life) and is therefore being sold so cheap. Also the Patriot is great value here, but even the Geils and Corsairs still score very high.

Again, memory kits are sometimes priced differently in Europe than in the US, prices and especially availability differs by country, and you'll have to look at all the variables to get the best possible deal in your region.

Let's round it all up on the final page >