This summary was done by Etherdude on DellTalk.


The Dimension XPS R350 was introduced well over 3.5 years ago. Since then, this basic case, power, and mechanical design has been an integral part of Dell''s high-end and later mid-range product line until the Dimension 4100 was replaced by the Dimension 4300 just a few months ago. Mechanically, the Dimension XPS Rxxx, Txxx, Txxxr, Bxxxr, Bxxx, and 4100 are NEARLY identical. Those of us who bought XPS R's and T's 2.5 to 3.5 years ago, were fortunate to have done so at the FRONT END of a hardware technology cycle. This cycle began with the PII and Intel 440BX/ZX AGP set, continuing on through the PIII, PIIIe, ill-fated RDRAM based i820 AGP set, and finally the i815 based machines such as the 4100. It ended with the introduction of the i845 AGP chipset supporting the Pentium 4 systems, which took over the mid range of Intel's (and Dell's) lineup from the PIII based machines.

These formerly top-of-the-line Dimension XPS R/T systems introduced Slot 1 CPUs, PC100 memory, AGP (2x) graphics, and integrated ATA-33 IDE interfaces and had a reasonable number of PCI slots. As a result of this, there are a number of current and near term upgrades that can be done to increase their performance by several fold (at least up to 3X overall). While the Coppermine based XPS T850r benefits very little from a CPU upgrade to 1GHz, the XPS R350 can easily gain a 3 to 1 CPU enhancement. Further, over the next 12 months, we MAY be able to benefit from next generation Tualatin based Celeron processors up to 1.5GHz. This could represent nearly a 5 to 1 scaling of performance of the basic motherboard/case over a 3-5 year life span. This is an unheard of "good buy" in our industry.

These CPU upgrades SHOULD be easy to do. Further, memory upgrades are inexpensive and also are straightforward. If you have an original 1997/1998 graphics card, it almost certainly is incapable of playing the newest games well, so video board upgrades are probably in your future. Finally, disk I/O performance can certainly be enhanced with the newest drives and controller logic at very reasonable costs.

While each of these upgrades can be very cost effective, done by itself, if you are looking to upgrade to Windows XP and are still running Windows 98 and Office 97 in a Dimension XPS R350-450 with 64MB to 96MB of clk=3 memory, an original really slow/noisy 6-8GB hard drive, integrated sound, and an early AGP video card, then the cost of purchasing all of the separate hardware and software components may exceed the cost of purchasing a whole new machine.

CAVEAT: These are relatively "old" machines and most are out of warranty, so while anything CAN be done, anything CAN also go wrong.

Key Facts: Dimension XPS Rxxx and Txxx/Txxxr

The Dell Dimension XPS Rxxx and Txxx(r) families of machines use the similar Intel SE440BX and SE440BX-2 motherboards. They both use the 440BX/ZX AGP set (most popular until recently in laptops such as the Inspiron 4000 and 8000). The software support for these from Microsoft is superb. The major functional difference between the two machines was the change from SECC (PII) to SECC2 (PIII) spec. in the Slot 1 CPU (largely a voltage regulation issue introduced by the first generation Katmai PIII processors in many of the XPS/T's) and the use of LED's instead of beep codes for boot diagnostics. Both the SE440BX and SE440BX-2 machines have a 100MHz front side bus (FSB), AGP 2X, and ATA-33 IDE.

Unlike 3rd party motherboard vendors, Intel rarely allows tweaks in their mobos. Further, Dell is usually as restrictive (sometimes more) in what features it exposes in its own version of the Intel BIOS. There are no clock or voltage tweaks accessible using the Dell BIOS. The current version is A13 for the XPS R and A11 for the XPS T. Use of Intel's BIOS (as opposed to the DELL BIOS) for these machiones is STRONGLY discouraged.

Memory Upgrades

Both machines can be upgraded to 768MB of PC100 SDRAM, ECC or non-ECC, CAS=2 or 3. Despite what Dell says, the SE440BX motherboard in the XPS Rxxx can use 256MB memory sticks. is an excellent source for memory and has been shipping 2-day Fed-ex for free. If we use fellow DelTalk member Rob Hancock's Crucial Banner ad on his Dimension Upgrade site to enter Crucial, we help Rob continue to keep his web site available to all of us.

Memory. prices vary, but as of early November, the price of 256MB, clk=2 PC100 memory is $27.89 (US only). For Windows 98/98SE/ME, 256MB to 512MB of clk=2 memory is recommended. For Windows NT/2000/XP, we recommend 384MB to 768MB of clk=2 memory. ECC is probably overkill for home use, but costs an extra $2/stick from Crucial. These machines will default to the lowest common denominator, so even if you spring for new clk=2, ECC memory, if you have even one stick of old clk=3, non-ECC memory, the whole machine runs clk=3, non-ECC.

Using an 800MHz Coppermine PIII, I have seen approximately a 10% (double word) to 15% (single word) hit in memory performance between clk=2 and clk=3 due to higher memory latency. I use SiSoft SANDRA or Memtach as my benchmark. If you are like many and have 128MB of clk=3 memory and want to make the next step in the least expensive way, then upgrading your memory to 256MB or 384MB with a single memory stick is worth more than speeding up the memory. However, if you are going to 512MB or above, then you will be buying at least 2 memory sticks, at which point it is generally more cost effective to just insure you have clk=2. Given the low prices today, more memory at the highest speed is ALWAYS a good deal. Further, the faster your CPU (remember those 1.5GHz Celerons next year!), the more important memory speed becomes.

You can tell if you have clk=2 or clk=3 memory by running a CPU utility like CPU-Z from . It will tell you the CAS/RAS settings under its Memory taskbar. Also, clk=2 PC100 memory with 1000MHz PIII should get SiSoft Sandra memory test numbers of around 310MB/s (single word) and 340MB/s (double word). These are reference numbers for the 440BX, clk=2. If your mileage varies (on the down side) you almost certainly have clk=3. On my PIII 800MHz system, clk=3 gets 260MB/s (single) and 292MB/s (double). Testing the same system with clk=2, we get 295MB/s and 333MB/s.

Processor Upgrades

The Dimension XPS R came with a 350MHz to 450MHz PII. The XPS T came with 450MHz to 850MHz PIII. These machines are potentially capable of running any one of up to 4 generations of Intel P6 micro-architecture with 100MHz front side bus. Today, the only effective upgrades direct from Intel are either the 850MHz or 1000MHz slot 1 SECC2 processors. Since Intel has stopped manufacturing these, availability will become increasingly limited (we think!). Currently, the best price and availability on the 1GHz part seems to be from at $200.00 plus shipping.

The families of relevant P6 processors include:

1. Deschutes - Intel Pentium II -.25uM technology - 350MHz to 450MHz. 512KB external half-speed cache. Available in Slot 1 SECC.

2. Katmai - Intel Pentium III - .25uM technology - 450MHz to 600MHz. 512KB external half-speed 4-way cache. Available in Slot 1 SECC2. Adds SSE instructions. NOT RECOMMENDED FOR XPS R UPGRADES

3. Coppermine - Intel Pentium IIIe .18 uM technology - 550MHz to 1100MHz with 256KB full speed internal 8-way cache. Celeron 2 to 1.1GHz with 128KB of 4-way cache. Available in Slot 1 (to 1GHz) or Socket 370 FC-PGA (to 1.1GHz) with slocket adapter. Most available current upgrade. Seems to work well with all XPS R/T (or even XPS/B but at 133MHz).

4. Tualatin - Intel Pentium IIIt - Speeds to 1.26GHz with up to 512KB full speed cache (PIII-Server/Mobile) - 133MHz FSB ONLY! Regular desktop PIII-T goes to 1.2GHz and has 256KB cache and 133MHz FSB. Celeron-T to 1.2GHz with 256KB one wait state 8-way cache and data pre-fetch with 100MHz FSB. New pin out and power requirements force changes to all PIII infrastructure. No Slot 1 format. Requires Powerleap PL-iP3/T (see: All models have data pre-fetch and deeper memory buffers for more efficient memory utilization. Intel will continue to upgrade the Celeron (for value market) and PIII-M (for mobile) market through most of 2002.

Since all Tualatin PIII processors run with a 133MHz FSB, we need to look into the Celeron family for upgrades past the 1.1GHz mark as we move into the future.

The Good:

1. The Tualatin Celeron has an 8-way set associative cache and data pre-fetch, so is slightly better performance per clock-cycle than the Coppermine PIII. Given that the cache is 256KB, it equals the Coppermine PIII and is MUCH better than the Coppermine Celeron.

2. Rob Hancock tested the Powerleap PL-iP3/T. Its performance substantially exceeds that of the 1GHz Coppermine PIII in my personal XPS R. See: . At $170.00 list price, it is less expensive than the increasingly unavailable $210 1GHz retail Coppermine Intel part. My comparisons of 1GHz performance vs. 1.2GHz performance are based on running EXACTLY the same tests that Rob Hancock ran using my own 1GHz PIII Coppermine XPS R. Like Rob, I ran SiSoft SANDRA 2001te, but I have clk=2 memory instead of clk=3. This software is available as de-featured freeware from

Results for my 1GHz PIIIE are consistent with known results and are:

Current CPU Dhrystone ALU 2660 MIPS
Current CPU Whetstone FPU 1327 MFLOPS
Current Processor, Chipset Integer SSE 5345 it/s
Current Processor, Chipset Floating-Point SSE 6541 it/s
Current Memory System Int ALU/RAM Bandwidth 314 MB/s (clk=2)
Current Memory System Float FPU/RAM Bandwidth 340 MB/s (clk=2)

Results for Rob's 1.2GHz Celeron-T are:
Current CPU Dhrystone ALU 3362 MIPS
Current CPU Whetstone FPU 1605 MFLOPS
Current Processor, Chipset Integer SSE 6516 it/s
Current Processor, Chipset Floating-Point SSE 8089 it/s
Current Memory System Int ALU/RAM Bandwidth 302 MB/s (clk=3)
Current Memory System Float FPU/RAM Bandwidth 316 MB/s (clk=3)

Please notice that the ratio between the two is between 1.21 to 1.26 to 1. This means that the Tualatin is actually slightly better than the Coppermine on a clock for clock basis. If Rob had clk=2 SDRAM, I would expect memory bandwidth numbers similar or just slightly better. SANDRA's CPU benchmarks seem nearly the same whether you have PC100 or PC133 memory (on the Coppermine PII), so I doubt that the CPU numbers would be dramatically different (maybe the FPU numbers might since they are double word memory references instead of single word).

3. Current information from Intel for the Tualatin Celeron-T shows the following roadmap - which is very much subject to change!:

Q4 2001: 1.2GHz Celeron - 0.13 micron Tualatin, 100MHz FSB
Q1 2002: 1.3GHz Celeron - 0.13 micron Tualatin, 100MHz FSB
Q2 2002: 1.4GHz Celeron - 0.13 micron Tualatin, 100MHz FSB
Q3 2002: 1.5GHz Celeron - 0.13 micron Tualatin, 100MHz FSB

In general computing benchmarks, a PIII 1GHz processor is roughly equivalent to 1.3GHz or 1.4GHz P4. Assuming linear scaling, by mid-late 2002, we could have a 1.5GHz Celeron-T that would be in the same raw performance class as the current Dimension 4300 with 1.6-1.8 GHz P4 and PC133 SDRAM.

4. If you expect to continue to run the same O/S (Windows 9x/ME NT/2000) and applications for at least another year, there are a number of very cost effective upgrades that can extend the life of your machine that require NO software work (or very little) and provide very substantial performance improvements.

The Bad:

1. At 100MHz, the FSB of the XPS R/T family has a bandwidth limit of 800MB/s. The useable bandwidth of this bus (using Memtach) is no more than around 500MB/s. Current P4 RDRAM machines benchmark as high as 1.7GB/s. With modern ATA-100 drives, high-end graphics processors, and much faster CPU's, these machines can easily become memory bound. It has already been seen that 1.06GB/s PC133 memory is a significant bottleneck on the mid-range 845-based P4's and can cause as much as a 30% application performance hit over identical RDRAM machines.

2. The Powerleap slocket adapter is not yet shipping in volume nor is there a lot of experience with it in the market.

3. Past 1GHz, we appear to be dependent on a single small vendor to provide the form factor, voltage, and signaling adaptation required to use the Tualatin processors in our now 3 generation-old motherboards. Given the vagaries of today's technology market, one must ask whether Powerleap will survive the current tech-depression? Answer unknown.

4. While the PIII Tualatin with 512KB cache used in the PIII-M and PIII-S almost (but not quite) matches the AMD Athlon family on a clock for clock basis, it requires a 133MHz FSB. The smaller Celeron cache and 100MHz FSB will become bigger factors as the core CPU clock rate increases.

The Ugly:

1. If you are upgrading to Windows XP, you MAY have a lot of work to do to. You need to round up the latest and greatest drivers for all of your random hardware. Since Dell is not providing Windows XP support for the XPS R/T, you will NOT be getting these drivers from Dell, but instead from the OEM's who produce the equipment in your Dell or from the support provided by Microsoft's on its installation CD. In any case, YOU are responsible for the system integration of your components into Windows XP, not Dell.

2. You may have to upgrade applications. You WILL end up having to re-install Outlook 97/2000/2002 due to differences between Win 9x and Win 2000/XP implementation. If you have religiously installed all patches like I have, this means re-installing all of Office, not just Outlook. This re-install looks like a NEW install due to Windows XP and will require a call to Microsoft to get "relicensed". If you install all of security and functionality patches for Office 2000 that I do, the process takes hours.

3. A new Dell computer will come with Windows XP already integrated to the hardware configuration you purchase. It will also come with Office XP (SBE or Pro) for a surcharge of $150-$350 over a basic Works install. These prices are roughly equivalent to (or better than) installing a retail Office XP upgrade from CompUSA. Plus you get a new Norton Anti-virus, Image Expert, WinDVD (for the DVD drive) and other free software from Dell that may require costly upgrades for Windows XP.

4. Currently, the Dell 4300 is limited by its 1.06GB/s of PC133 memory bandwidth. This is especially so because the P4 is more "memory intensive" than the PIII. By early next year, Intel should be supporting DDR 845 chipsets (Double Data Rate) for Dimension 4300 class machines. This will allow 2.1 GB/s (133Mx2) to 2.7 GB/s (166Mx2) of low-latency memory to the bandwidth hungry P4. Further, the P4 will have been moved to a .13 uM process. This is expected to reduce power consumption, increase the cache size to 512KB, and support MUCH higher clock rates (easily to 2.5GHz+). Within 3 to 6 mos., 6 to 9 at most, I can easily envision a Dimension 4300-class machine ($1300-$1800) at 2.0GHz+ with equal or more raw performance than today's highest end Dimension 8200 ($2200-$2500).

SUMMARY: I think that up to $200 spent on a CPU upgrade for the Dimension XPS R/T machines, GIVEN that the rest of the machine is in good condition and has reasonably current HDD's, memory, and video, is a good investment.

Machine 1:
Dell Dimension XPS R400->800 PIII, WinME with ALL patches, 384MB PC100 ECC (3 sticks), ATI Xpert 98 2X AGP, Promise Ultra ATA-100 TX2, Maxtor Diamond MAX 45 52049H3 (20.5GB - ATA100), Maxtor Diamond MAX 40 52049H4, 20.5GB - ATA100), NEC 40X CD-ROM, ZIP 100 IDE, 3COM 3C905B/C (Qty 2), Turtle Beach Montego I A3D Audio, USR 56K Voice Winmodem

Machine 2:
Dell Dimension XPS R400->1000 PIII, WinME with ALL patches, 512MB PC100 (2 sticks), ATI Radeon 7500, Promise Ultra ATA-100 TX2, Quantum Fireball AS (20.5GB - ATA100), Maxtor 91152D8 (11.5GB - ATA33), IBM DHEA 38451 (8.5GB - ATA33), Creative Ovation 12X DVD, Sony CD-RW CDR140 8/4/32X, Crystal 4611 Audio SE440BX), PCTel 56K V.92 PCI Modem, C-Net Pro 200 10/100 LAN