Abit BM6-ZM6: it promotes for Celeron PPGA
April 15 of 1.998 could be a fatidical date for AMD. This day Intel announced the Celeron, his weapon for the assault to the only stronghold that AMD had left in the eternal battle between two microprocessors manufacturers: the market of scale average - fall.
Nevertheless, soon it was warned that the decision to sell the Celeron without any cache memory by no means was penalizing in excess the yield of the mike, granting to the mark Celeron awful reputation that still today drags. What is more, on having wasted this perfect opportunity to give the brad to his rival, AMD had time to present the K6-2, with much his most successful mike up to the date.
Pero Intel does not commit the same error two times: in a few months it presented Celeron Mendocino, a Celeron with 128 Kb of cache memory, capable of facing worthily even the very same older brother Pentium II. This time the problem was that, despite being assined to a market where the price is the factor number 1, it neither was an excessively cheap mike of making it was not even based on a cheap motherboard like the K6-2.
So finally Intel decided to solve the topic once and for all, extracting the Celeron PPGA, which are not but Mendocinos in format PGA (like the outstanding figure of the Pentium or K6-2 but of 370 pines), what allows to integrate them in badges of very accessible price. Two of these badges are the Abit BM6 and ZM6 that occupy us.
Two twin sisters?
When I received the badges to prove them (from Taiwan... less evil that Abit pays the mailing), ;) my first impression was that an error had been committed. They were exactly equal! Very well, not; one was taking writing "AB-BM6" and another "AB-ZM6", so they had to be different...: but in what?
From the physical point of view, they are identical: both have 3 sockets for memory in format DIMM, both have 1 slot AGP, 5 PCI and 2 ISA, and the disposition of the elements in the badge is the same. In fact, the only visible differences are some piece of different provider, what almost safely is due to the fact that they have been made in different date.
The differences come in the logical part; in particular, the BM6 incorporates the chipset BX and the ZM6 the ZX (not, the names are not very original, the truth). This implies some differences as for his capacities, especially as for the memory quantity instalable.
Before continuing, let's throw a glance to the technical characteristics of both badges:
Strangely similar, truth? Keep on reading to know how and the porqué of the small differences (or are not they it so much?) between both badges.
The importance of a good chipset
I have always said that to say "a computer Pentium II" is the same that not to say anything. To know the authentic potency and quality of a PC, we need to know not only the type of mike and his speed, but also the quantity and the type of memory that it incorporates, his videocard... and especially in what motherboard everything is installed.
And as the motherboard is controlled by the chipset, in fact the first thing on that we should concentrate is in this one. A good chipset will allow us to extend the motherboard to new models of mike or to more memory, will give us support for AGP or USB, or simply it will optimize the yield of the microprocessor over what it would do a mediocre chipset.
The chipset BX is, presently, the king of the scale Intel for normal Pentium II (not Xeon). It admits a maximum of 1 GB of memory, has support multiprocessor, bus up to 100 MHz... and also it is condenadamente rapidly, more than the solutions of other manufacturers like ROUTE or ALI.
The ZX is a very recent chipset, which we can consider to be a cut away version of the BX. Cut away as for characteristics (it admits as maximum 256 MB of memory and does not have support multiprocessor), that not as for yield, since in addition to an almost traced design of that of the BX also he supports speeds of 100 MHz bus.
And very much eye on this of the bus: there exists another version (more economic) of the ZX, call ZX66, which only differs from the ZX into which it admits a 66 MHz maximum bus, what would prevent us from using it with mikes as Pentium II to 350 MHz or more... at least officially, since they exist you would be doubts if there are the same chipset but in two different manufacture qualities, one capable of working fiablemente to 100 MHz and other one not.
The chipset ZX66 there is posicionado comfortably in the badges sector for Celeron, since this mike (so much in his version for Slot1 as in the PPGA or Socket370) uses a 66 MHz bus. Also LX, one is used very much in this sector ancient chipset quite well except for limiting ourselves to a 66 MHz bus, and EX-, a cut away version of the LXth, slightly advisable in general.
But if the Celeron do not use a 100 MHz bus: why in Abit do they get involved in using the BX and the ZX? For three motives:
Differences between the badges
Since we have already said, they differ in the chipset. And what implies this, he will wonder? Well, the first consequence is that the BM6 admits a maximum of 768 MB of memory and the ZM6 only 256 MB. The fact that the BM6 does not come up to the theoretical maximum of the BX of 1 GB it is due to the fact that 512 MB modules still do not exist and to the fact that it has 3 memory sockets instead of 4.
It is clear that it is convenient to wonder if one day we are going to come to these maxima. Nowadays, to use applications ofimáticas or games 64 MB are more that in abundance, and even being employed at serious applications as CAD or edition of video, 256 MB are many MB...
The second consequence is also relative to the memory, and it is a question of the impossibility of the ZM6 of using simultaneously modules of double face (double sided) in the sockets DIMM2 and DIMM3. Is it clear, no? Very well, perhaps NOT. Let's see: a module of double face is one with chips in both sides of the module (although they might be only in a side but with the connections as if they were in both faces, but it is much rarer). In general, the 64 MB modules are usually of the only face or single sided, while those 128 MB are usually double sided.
This limitation does that most of the badges with the chipset ZX ó ZX66 include only 2 sockets for memory, which might be filled by 2 128 MB modules. Nevertheless, Abit offers us a third socket to be able to gain access to other combinations like 128+64+64 ó 64+64+64, being the latter one of the most advisable since we would come up to a few excellent 192 MB with modules of 64 MB of the only face (much more common and compatible some with others that the 128 MB modules).
And the third and last difference is that the ZM6 can only use 4 as a master's degree of 5 slots PCI, while the BX can use all his slots PCI in this way. This is of a very relative importance, since not only there exist numerous cards PCI that do not need to be employed at a slot of this type, but also the slot not master's degree will be the quarter or the fifth one, and the fifth one for space reasons ISA is shared by the first card, so perhaps even we never go so far as to use it.