AMD 780G Chipset and Athlon X2 4850e Preview

As enthusiasts, we’ve been getting the most worked-up over the implications of AMD’s Hybrid Graphics and multi-monitor features. The 780G story is more complex than playable frame rates and massive monitor arrays, though. You also have to factor cost and power consumption into the performance equation, especially since integrated chipsets are popular in the corporate world, where a few watts of power savings multiplied out across 500 workstations turns into big money.

AMD let us know that the Gigabyte motherboard we’ve been testing will sell for somewhere between $80 and $90. We were even able to find a couple before the official launch priced at $99. Adding a Radeon HD 3450 card for Hybrid Graphics adds roughly $50 to the bottom line. Now you need a CPU in tune with the platform’s energy efficiency, powerful enough to put up a fight in the latest games, and at the same time, be cost-effective. Enter AMD’s new Athlon X2 4850e, successor to the low-power Athlon X2 BE-2400.

If you’re familiar with AMD’s pricing structure, then you know the company draws a clear line between its dual-core Athlon 64 X2s and energy-efficient Athlon X2s. The former range from 2.1 GHz to 3.2 GHz and consume anywhere from 65W to 125W. They’re all AM2-based chips with 1 GHz HyperTransport links, but include 2MB of L2 cache to help augment performance. Conversely, the Athlon X2s range from 1.9 GHz to 2.5 GHz, sport the same 1 GHz link, but get a 45W rating thanks to a cut-back 1MB cache and 65nm manufacturing node. The 4850e is AMD’s new flagship for that low-power, dual-core lineup.

Why did AMD completely change the family’s naming convention on a simple speed bump? Nobody seems to know. AMD says the new nomenclature is tied to the standard-wattage X2 chips. At the same time, it isn’t changing the names of existing energy-efficient X2s. Sounds like a recipe for customer confusion to us. Nevertheless, the Athlon X2 4850e is architecturally identical to the Athlon X2 BE-2400 that precedes it. That means 256KB total L1 cache, 1MB total L2 cache, dual-channel DDR2 memory support at speeds up to 800 MHz, and AM2 socket support.

The 4850e operates at 2.5 GHz, yet still dips in at that 45W max thermal power rating. Clearly, the CPU is a good match to the 780G platform. AMD is also pricing the CPU at $89—well below the $104 it was asking for the BE-2400 and far less than any of the company’s quad-core Phenom chips. The 4850e shapes up well against Intel’s lineup, too. The closest competition, based on price, is the dual-core Pentium E2200 running at 2.2 GHz. The Allendale-based processor is rated at 65W, runs on an 800 MHz bus, and sports 1MB L2 cache. That’s the chip we chose for our comparative tests.

Gigabyte’s GA-MA78GM-S2H Motherboard

AMD sent us a production-level Gigabyte GA-MA78GM-S2H as a means of testing the 780G chipset and Athlon X2 4850e processor. It comes as no surprise that the board fully showcases what the platform can do.
 

The first thing you’ll notice is that the northbridge and southbridge are cooled passively. Both components run hot under load, but our setup ran stably throughout testing. AMD’s reliance on 55nm manufacturing pays off in spades here, as the competent DirectX 10 graphics engine does its job in complete silence.

Although the GA-MA78GM-S2H fits onto a microATX form factor, the board comes loaded with integrated functionality. As mentioned you have a choice of three display outputs. The 15-pin VGA connector is tied to one of the display controllers, while the DVI and HDMI outputs share the other. Naturally, only one of the two can be used at any given time. The rear I/O panel provides access to four USB 2.0 ports, one FireWire 1394 connector, an eSATA port, Gigabit Ethernet, enough 1/8” mini-jacks for analog 7.1-channel output, and an optical audio port.
 

Onboard, you’ll find five more SATA ports, enabled through the SB700 southbridge. A single floppy connector is available, though with Vista pulling storage drivers from CD or USB, there’s even less of a reason to revisit the legacy medium. A single parallel ATA connector takes up to two devices in case you’re still using an older optical drive. Expansion consists of a single PCI Express x16 slot, two PCI slots, and one PCI Express x1 slot.  Should you find yourself looking for extra USB or FireWire connectivity, onboard headers pave the way for additional ports.

Depending on the CPU you’re using, Gigabyte says its GA-MA78GM-S2H supports up to 16GB of DDR2-1066 memory across four slots. Because the Athlon X2 and Phenom chips employ dual-channel memory controllers, you’ll want to populate those slots two at a time for optimal performance. Two 1GB modules should give you plenty of memory for system tasks, while enough is tagged for the graphics core (default in the board’s BIOS is 256MB).
 

Just because the motherboard is intended for a more mainstream user doesn’t mean it’s completely devoid of BIOS-based overclocking options. Gigabyte enables its MIT (MB Intelligent Tweaker) interface, facilitating complete control over the board’s HyperTransport link speed, integrated graphics core clock, CPU ratio, CPU host clock control, PCI Express frequency, and memory clock speed. Additionally, you’ll find a full range of voltage controls, from DDR2 memory voltage to northbridge and CPU voltage tweaks. We’re not quite sure how much overclocking someone buying an IGP-based platform is going to do, and AMD explicitly exempts itself from damage caused to the system as a result of running out of spec.