Athlon II X4 620

Basically, it is a Deneb core which drives all the Phenom II models with some variations here and there. Instead of just shrinking the size of L3 cache by disabling it, like AMD did with the Phenom II X4 800 Series, it is completely absent from the Athlon II X4 core die, thus you get – Propus.


Image courtesy of mAJORD from XtremeSystems.

It is designed to offer decent performance in all kinds of applications at a very low price point, for a quad core processor. Its main competitor for the time being will be, by now little outdated, Intel's Q8x00 series, but we will go through that comparison a bit later in tests. Unlike the Regor core design where AMD tried to make up for lost L3 cache memory by upping the L2 cache to 1 MB per core, Propus comes with stock 512 KB L2 cache memory per core. So yes, it is a Deneb without L3, and yes, some bins could be L3 cache unlockable if AMD used Deneb cores with locked L3 cache to meet the market demands or to get rid of some cores that can't qualify for Phenom II processors.

As for our Athlon II X4 620, it is based on a K10.5 architecture like any other Phenom II or Athlon II processor. It comes with an integrated dual-channel memory controller, with support for both DDR2 1066 MHz and DDR3 1333 MHz memory standards. It is primarily designed for socket AM3 motherboards, but any AM2+ motherboard with proper BIOS update will support these processors, like with any other Athlon II/Phenom II.

The frequency for this model is set to 2.60 GHz using upwards locked 13.0x bus multiplier. It's not a Black Edition, so the only way to overclock this processor is by increasing the HT value, while downclocking can still be achieved by lowering the bus multiplier.



What's interesting to see, is that although Propus is missing an L3 cache, the TDP is still declared at 95W, like many Phenom II X3 and X4 models. The consumption measurements will surely show lower values than Phenom II X3 or X4. It is a bit surprising to see AMD not using any marketing tricks and declare it with lower TDP. The trick is in core voltage which for Athlon II X4 ranges from 0.925V to 1.425V. The lower the operating voltage, lower the overall power consumption.

First batches, like our Athlon II X4 620, will come at higher operating voltage, around 1.40V. This enables AMD to quickly get rid of all those Denebs with bad L3 cache, and increases the maximum stock overclocking limits, which is always a good thing to see in early reviews.

Later we will see models with lower TDP and energy efficient models that operate at slower frequencies and much lower TDP ratings, just 45W. These will be known as Athlon II X4 600e series, and for starters, two models are planed for release in the near future, 600e that operates at 2.20 GHz and 605e that runs at 2.30 GHz frequency.

There are no cutbacks in the feature support compartment for AMD's new Athlon II Series. It supports everything Phenom II supports, including MMX, SSE2, SSE3, SSE4A instructions, Enhanced 3DNow!, NX bit, AMD64, Cool'n'Quiet, and AMD-V technology. Many companies will be happy to see virtualization support in a cheap quad core processor. Intel made a mistake with the Q8200, which doesn't have support for Intel VT, but that's now corrected by the recently introduced Q8400 model. The recommended price for Athlon II X4 620 stops at $99, which makes it the first quad-core processor to be launched under $100 mark.

So all in all, Athlon II X4 600 looks like a serious competitor in an already overcrowded $100-$150 segment, and it intends to bring some extra cores to the party. The only big question that remains is whether the lack of L3 cache will limit the performance of the Athlon II X4.

With the L3 cache gone, four cores have no way of storing or sharing instructions between themselves. We don't know the status of Cross-bar that is used to transfer instructions between the cores, but we are waiting for answer from AMD and will update the review accordingly. Theoretically this translates into big performance bottlenecks, as fewer CPU instructions can be stored into small L1 and L2 caches, and if needed instructions aren’t there, the CPU core must request it from much slower system memory.

To find out how much of performance hit removing L3 cache will have, you find a fully potent Phenom II X4 965 in our benchmarks, but clocked down to 2.60 GHz, same as Athlon II X4 620. This will result in an apples-to-apples comparison to easily assess the impact of the missing L3 cache.

Specifications

In the table below you can review detailed specification of Athlon II X4 620 and other models. Note that the Phenom II X4 965 shown here will be scaled down to 2.60 GHz. As explained further up, this is done to show the performance drops caused by the lack of L3 cache.

Two Intel processors, Core2 Duo E8200 and Core2 Quad Q8200 are picked to be sparring partners for new Athlon II X4 620. Both should be in a similar performance segment, but at a much higher price point.